Minimum delay or maximum efficiency? Rising productivity of available capacity at airports: Review of current practice and future needs

Around the world airports are facing capacity constraints more and more everyday, generally the runway capacities are restricted by governments and airports are unable to accept additional aircrafts. Technological improvements can decrease the necessity of policy limitations in terms of noise and air pollution. Rapidly increasing numbers of traffic developed severe scarce capacity, congestion and delay problems and the capacity that is available, needs to be allocated as efficiently as possible. Airport capacity can be allocated in different ways; administrative capacity management with slot allocation and traffic distribution rules; market-based capacity management with slot auctioning, secondary trading and peak pricing; a combination of both mechanisms; and no regulation mechanism as applied in the USA with the exceptions of busiest airports. The review contains the analysis of current state of practice and the review of relevant research on capacity and slot allocation modelling with policy and demand management perspectives. It targets identification of existing problems, inefficiencies, gaps and requirements in current practice of slot allocation mechanisms, defining options for change in policies to allocate slots more efficiently, transparent and fair by investigating market-based mechanisms. The objective of this paper is to contribute to the ongoing research for improvements to the slot allocation process that can be rationally implemented in practice in order to improve efficiency, fairness and transparency. For that purpose, based on these slot allocation approaches, we provide a critical review of status-quo, literature and current research with demand and congestion management perspectives by considering overall social welfare, airline and airport surplus, passenger welfare and explore hypothetical, computational and practical challenges that have arisen from cross-disciplinary methodologies.     

Airport slot allocation: a time for change?

The increasing imbalance between airport capacity and traffic resulted in exceptional congestion and delays drawing the attention of aviation policy makers towards airport demand management for the allocation of scarce airport slots. Attempts to bring forward airport demand management measures in the form of airport slot allocation were not widely adopted and have not flourished in practice. This paper aims: (i) to apply a methodological framework for the selection of the most suitable slot allocation strategy for various types of airports, (ii) to explore potential impacts such that measures or strategies can bring about, and (iii) to assess the suitability of the existing airport pricing scheme and the potential implementation of a new policy regime aiming to bridge the gap between growing traffic and scarce airport capacity.     

New potential hubs in the South-Atlantic market. A problem of location

Hub-and-spoke networks have become very popular in the airline industry. In this paper we study the potential hub candidates in the South-Atlantic market if a future process of liberalization creates a common air market area between South America and Europe. The analysis is based on the principal operating strategies that airlines consider when they choose their network configuration: central location in the market, local traffic at the hub cities and airport facilities. Traffic levels, great circle distances between the airports and other variables are used to analyze possible differences among airports. Other implications concerning the agents involved like gains in frequencies, time penalties and burden of capacity are also explored. Results of the analysis are used to extract some policy considerations and to stimulate discussion by government officials, air industry analysts and academics, about the necessity of the introduction of more liberalized measures in emergent markets.     

Operational performance evaluation of international major airports: An application of data envelopment analysis

This paper uses data envelopment analysis to assess the operational performance of 20 major airports around the world. It is found that the form of ownership and the size of an airport are not apparently correlated with operational performance of airports. In contrast, the existence of a hub airport, the location of the airport, and the economic growth rate of the country in which the airport is located are all related to the operational performance of airports. The 20 airports are put into four groups according to their efficiency values.     

Hub competition and travel times in the world-wide airport network

The aim of this work is to measure the competition between airport hubs based on an analysis of travel times in the world-wide airport network. By considering the minimum travel time required to connect each pair of airports, it is possible to create new measures of hub competition, separating the effects of hub position and temporal coordination. This analysis was carried out at the global level, considering all 232 airports with more than 3 million seats yearly offered in departure flights in 2008, and also in relevant geographic markets. The results show a high level of competition among the most important world airports, but the major airports of Europe have a geographical advantage in relation to world markets over the major American and Asian airports. We also show that airports located in different continents often compete for the same origin–destination markets. Geographical position appears to be the most important variable explaining hub performance. Secondary hubs show a higher degree of specialization towards specific markets.     

Management of airport congestion through slot allocation

The lack of airport slots (the time allocated for an aircraft to land or take off), particularly at airports which experience congestion, have reached unmanageable proportions in recent years. The International Civil Aviation Organization (ICAO) records that, by the end of 1997, there were 132 slot controlled international airports. The World of Civil Aviation, 1997–2000. ICAO Circular 273-AT/113, p. 12 (118 year round and 14 during peak seasons). Between 1989 and 1998 the reported number of commercial aircraft in service increased by about 60% from 11,253 to 18,139 aircraft. In 1998, 1463 jet aircraft were ordered, compared with 1309 in 1997, and 929 were delivered compared with 674 aircraft in 1997. In 1998, the total scheduled traffic carried by airlines of the 185 Contracting States of ICAO amounted to a total of about 1462 million passengers and about 26 million tonnes of freight. These figures¹ are reflective of the rapidly increasing frequency of aircraft movements at airports, calling for drastic management of airport capacity. To cope with the demand, airlines are forming strategic alliances with themselves by utilizing such commercial tools as franchising, leasing and interchange of aircraft. The management of airport capacity through slot allocation is a critical consideration for the world aviation community. This article analyses the problem and discusses various issues related thereto.     

Whether low-cost-carrier passengers spend more on duty-free goods at the airport? Evidence from Incheon International Airport

With a dramatic growth in the low-cost carrier (LCC) traffic around the world, many airports have built budget terminals to accommodate the LCC flights with cheaper airport charge to the airlines but inferior shopping environment and service quality to the passengers. This study aims to answer the following research questions: i). Whether the LCC passengers have higher purchasing power than FSC (full-service carrier) passengers for the airport concessions, particularly the duty-free goods? ii). Would the budget terminal design contribute to or jeopardize the LCC passengers' airport concession expenditure? iii). How could the airport operator maximize its concession revenue by re-designing terminal or re-allocating flight slots? We collect the actual airport duty-free transaction data from Incheon International Airport (ICN) for an empirical investigation. Our empirical evidence first suggests that LCC passengers could have comparable or even higher purchasing power than FSC passengers in consuming duty-free goods at the airport. Among all the LCC passengers, Chinese have the highest purchasing power. Second, the inferior shopping environment and service quality of budget terminal seriously jeopardize the duty-free sales from the LCC passengers. Third, counterfactual analyses show that, if ICN could convert its budget terminal into a conventional terminal, 44 million USD more duty-free sales can be generated per year. Even keeping the current terminal design, re-allocating the LCC flights between the budget terminal and conventional terminal could bring approximately 4.9 million USD more duty-free sales per year. The findings provide managerial implications to ICN and other airports for effective airport revenue management. First, the budget terminal design may not be ideal to accommodate LCC traffic as it damages the concession revenue from particular LCC passengers with high purchasing power. Second, exploring the concession revenue from the growing LCC traffic could help maintain an airport's advantage in aeronautical charge under single-till regulation.     

The effects of deregulation, changed customer requirements and new technology on the organisation and spatial patterns of the air freight sector in Europe

Customer requirements, new technologies and the deregulation and liberalisation measures of the last 15 years have had a significant influence on market structures in air freight transport in Europe. The study examines the sector using the concept of global production networks. It describes the reorganisation in various dimensions. Firstly, there is the development from single air freight forwarders to global networks of firms. Secondly, we find a reorganisation of inter-company relations. Thirdly, airlines around the world organise their air traffic as a hub system. This lends added importance to the selected hub airport, and puts pressure on them to enlarge. As spatial consequences there is greater competition among international airports.     

Optimising flight connection times in airline bank structure through Simulated Annealing and Tabu Search algorithms

In hub and spoke airline networks, flight arrivals and departures generally have a bank structure to increase connections among spoke cities through a hub airport in order to provide cheaper service for higher volumes of air traffic. In this study, we introduce the airline bank optimisation problem with a novel mathematical model for improving flight connection times. The mathematical model aims to minimise the total connection times for transfer passengers and generates flight schedules regarding slot capacities in the hub airports. Since the problem is a combinatorial optimisation problem NP-hard and computational complexity increases rapidly for real-world problems, we employ the simulated annealing and the tabu search algorithms to achieve better solutions in a reasonable time. We generate sub-problems using real-world data and investigate the effectiveness of the algorithms. Finally, we present the results of a real case study of a Turkish airline company which has a hub airport connecting the flights between Middle Eastern and European cities.     

Substitution and complementarity in aviation: airports vs airlines

In this paper a model concerning substitution and complementarity on the linkage between airport facilities and airlines from the viewpoint of pricing policy is formulated. This model is used to analyze whether airport pricing policies, e.g. to ensure cost recovery, are compatible with competition for transfer passengers. It is found that airports with a high volume of demand can pursue cost recovery and still be the most preferred hub. Airports with a low level of demand will not be the preferred hub, even if the larger airport charges higher taxes to recover costs.     

Evaluating financial performance of commercial service airports in the United States

Studies on airport performance have focused primarily on productivity and operational efficiency. There are very few studies on airports’ financial viability and strength, especially those in the United States. Most of the U.S. commercial service airports are government-owned entities and operated for the service of the community rather than for profit, but expected to be financially self-sufficient and raise capital funds mainly through the bond markets. However, past studies of the financial performance of U.S. airports have relied on traditional profitability measures and financial efficiency measures that are more appropriate for airports owned and operated by for-profit entities. Based on the literature for non-profit organizations and the practices of credit rating agencies and government oversight bodies, this paper adopts six pertinent financial performance metrics to measure and compare the operational financial performance, leverage, and liquidity of 60 large and medium commercial service airports in the United States during the 2010–2017 period. The paper further examines factors that may affect airport financial performance. The results reveal that large hub airports have better liquidity while medium airports have better leverage during the study period. These results suggest that the effect of airport size on financial performance is inconclusive. Regression analysis shows that airports with high productive efficiency and those without a dominant carrier tend to have more surplus revenues for meeting their operational financial needs and capital spending and have better liquidity. The paper highlights the importance of using appropriate metrics to evaluate the financial performance of public sector entities and provides relevant information to bond investors. The devastating impacts of the COVID-19 pandemic on airports accentuate the significance of leverage and liquidity. Therefore, the financial metrics discussed in this paper would help support public policy debates and allocate public funds to the airports.     

Airport–airline vertical relationships,their effects and regulatory policy implications

This paper examines the forms and effects of vertical relationships between airports and airlines with a focus on the North American and European aviation markets. We find that such vertical relationships enables those participating to achieve various benefits and may be formed as a competitive response to other competing airport–airline alliances. In some cases, vertical airport–airline relationships strengthen the hub status of major airports, leading to increased employment and service quality in local markets. On the other hand, preferential treatment of a particular airline by an airport may enhance that airline’s market power, allowing it to dominate the airport and charge hub premiums. The competition and welfare implications of airport–airline vertical alliances can be complicated and two-sided, subject to the influences of other factors such as the market structures of the airline and airport markets.     

The impacts of emerging aviation trends on airport infrastructure

The demands on airport infrastructure around the world are both growing and changing. This paper explores what problems these changing demands imply for airports, and how they are coping with them. Growth in demand imposes a problem of allocation of scarce capacity in the short run—how well mechanisms such as the slot system are coping with them is explored. In the long term, increases in capacity are warranted, and how the emerging ownership and regulatory environments for airports will handle these is examined. Changes in patterns of demand will come from new business models, such as low-cost carriers and from new aircraft types, such as the Airbus A380—the implications of these for airports of these are considered. Finally, the issue of airport cost efficiency, and how ownership and regulatory environment impact on it, is examined.     

The welfare effects of the allocation of airlines to different terminals

Many airports around the world have recently built, rebuilt or are in the process of constructing new terminals. Incumbent airlines and new entrants must be allocated to the new and old facilities. When spaces at airport terminals are directly allocated, the allocation should be done by taking into account the implications for airlines’ competition and social welfare, given the airlines’ network configuration. We use a theoretical model in which two airlines compete in prices with differentiated products for a given network structure. The model shows that, in general, if airlines are allocated to different terminals, the level of competition is reduced, the ticket prices are higher and the consumer surplus and social welfare are lower. Only in some routes, and under certain conditions on the market size, ticket prices may be lower.     

Slot auction in an airport network with demand uncertainty

This paper investigates the effectiveness of airport slot auction by developing a two-stage model, which distributes slots among competing airlines using an ascending-bid multi-unit auction. Airlines assign different values to slots at peak and off-peak periods, and each carrier has its private (subjective) forecast of future demand. Conditional on the slots available to them, airlines compete in frequency, fare, and aircraft size over a congested airport network. The market outcome under such a scheme is benchmarked to those under an ex ante allocation and an ex post allocation by a social planner. Comparison results suggest that the auction-based scheme is inferior to the other two schemes when there is little fluctuation in demand, whereas the auction-based system is more effective when there is substantial demand uncertainty. Auctioning some grandfathered slots can improve social welfare but the marginal effect may diminish quickly.     

What is the busiest time at an airport? Clustering U.S. hub airports based on passenger movements

Accurate clustering of airports enables airport authorities and operators to precisely position themselves in the competitive market, facilitates airlines to efficiently allocate resources, and empowers the research community with credible data for new discoveries. Existing clustering studies largely use traffic volume, network connectivity, or operational efficiency to group airports into hierarchical clusters or parallel partitions. Developing a different perspective, this study focuses upon a key bottleneck of outbound passenger movements in airport terminals, the security checkpoints, and uses the Transportation Security Administration (TSA) Customer Throughput/Wait Times Reports to cluster hub airports of the United States. With the input data structured as univariate time-series, k-shape, a clustering algorithm that is robust to time axis distortion and computationally efficient, is selected to analyze the similarity of time-series using shape-based distance. The clustering results are validated by examining the raw and z-normalized data of selected airport clusters on six sampled dates. Analysis results indicate that k-shape is competent and efficient to process and cluster time-series data used for this specific research. This study offers a fresh perspective to cluster commercial airports using an infrequently employed dataset. The clustering results reveal how the geographical location, hub status in airlines' operational network, and destination type of an airport affect the movement of outbound passengers through terminals     

Concession revenue and optimal airport pricing

In recent years airports have been under growing pressure to become financially self-sufficient and to pursue profit maximization in their non-aeronautical or concession operations. In this paper we examine the optimal pricing in a model where concession and aeronautical operations of an airport are considered together with an overall break-even constraint. We find that the optimum solution may require a subsidy from concession to aeronautical operations. However, such a cross-subsidy may or may not restore marginal-cost pricing on aeronautical operations. On the other hand, social welfare can be higher when an airport is allowed to make profits in concession operations than when marginal-cost pricing is imposed on concession operations.     

The role of London airports in providing connectivity for the UK: regional dependence on foreign hubs

In a context of ongoing debate about the future UK aviation policy and its implications for regional economic development, this paper discusses the role of London Heathrow and the South East airports in providing connectivity for the UK, with particular focus on the international markets that originate from regional UK airports. Using an MIDT dataset of worldwide passenger itineraries served by the European airport network during May 2013, we first establish whether London Heathrow can currently be considered the most important hub for the UK, in terms of traffic generation, connectivity, and centrality, while also measuring the dependence of UK regions on foreign airports and airlines to remain connected with the rest of the world. Results show that, despite the competition, London Heathrow benefits from its massive traffic generation to remain the most central gateway for overall UK air transport markets. However, when only regional markets are considered, significant dependence on foreign hubs appears in many destinations, particularly to Asia–Pacific or the BRIC countries where above 80% of passengers use transfer flights. These results fit nicely with the observed trends of seat de-concentration and hub-bypassing in the airline industry. While dependence on foreign hubs can be interpreted as a sign of vulnerability, there is also the argument that bypassing Heathrow allows regional airports to develop new markets and reduce the level of congestion in the London airport system.     

The impact of airport capacity constraints on future growth in the US air transportation system

This paper simulates airline strategic decision making and its impact on passenger demand, flight delays and aircraft emissions. Passenger flows, aircraft operations, flight delays and aircraft emissions are simulated for 22 airports in the US, under three airport capacity scenarios. The simulation results indicate that most system-wide implications for operations and environmental impact seem to be manageable, but local impacts at congested hub airports may be significant. The response of the air transportation system to avoid airports with high delays could significantly impact passenger demand and air traffic for these and directly dependent airports. The simulations also suggest that frequency competition effects could maintain flight frequencies at high levels, preventing a significant shift toward larger aircraft, which would otherwise reduce the impact of the capacity constraints.     

Estimating the sensitivity of small airport catchments to competition from larger airports: A case study in Indiana

An accurate estimation of airport catchment area enables airlines and airport operators to make informed decisions and to target potential markets precisely. This study uses the state of Indiana as a case study to estimate traffic leakage from the local airport, Indianapolis International Airport (IND), to two large hub airports in Illinois, the neighboring state of Indiana, namely Chicago O'Hare International Airport (ORD) and Chicago Midway International Airport (MDW). By using a decision making model that considers flying cost and access cost, this study simulates from local passengers' perspective which origin airport delivers the most cost effective flight itinerary. Using the top 20 routes of IND in 2018 as model inputs, the catchment area of two Chicago based airports in Indiana with variable coverage is plotted for different traveling scenarios. The analysis shows that an airport catchment area is sensitive to location, service level and traffic volume of competing airports nearby, as well as purpose of travel (business or leisure), number of travelers in a group (single, couple, family or multiple), length of trip, destination (domestic or international), preference of airlines (network carrier or budget carrier), and frequent flyer program status (premier member or general member). These findings could be valuable to all three aforementioned airports as well as airlines serving these airports when allocating operational and marketing resources. More importantly, this study creates a generic model that could be used by virtually any airport to estimate scenario-based catchment area using readily available itinerary and spatial data without resorting to expensive passenger surveys.