PITFIELD, D.E., 2009. The assessment of the EU–US open skies agreement: the counterfactual and other difficulties. Journal of Air Transport Management, 15, pp. 308 - 314.
The advent of the EU–US Open Skies Agreement has been widely anticipated. A number of consequences
have been predicted, for example, impacts on fares, on passenger volumes, choice and on consumer
welfare. Airline costs are also predicted to fall as a result of increased competitiveness and increased
cooperation among airlines. In the short period since the implementation of the Agreement, it is relatively
easy to assess the supply-side changes that have been made, but more difficult to make wider
judgements. For example, can traffic growth be attributed to Open Skies and does airline and alliance
market power result in less fare flexibility with consequently less influence on changes in passenger
volumes? Have airline costs changed and what has been the source of the savings? This paper offers
some insight into the data that will be required to make these and other wider judgements and discusses
some methodological difficulties.