Access to airports is a major influence on passenger distribution among competing airports, and the level of service of the available modes also affects the observed modal split at each airport. Access to the airport is an integral component of the passenger's trip from origin to final destination. Improvements at an airport therefore need to be matched by ensuring that the level of service of the airport's access system is also adequate. Evaluation of level of service for airport landside, in particular the terminal, has been given research attention. Little research has been done to measure the level of service of access to airports, yet these measurements are required by airport management to improve access or formulate policies to influence modal split. Research in level-of-service evaluation to airport access using psychometric techniques is discussed. The raison d'etre of the methodology is to provide scale values of level of service and use of the scales developed to investigate the effects of level of service on mode choice. The method was applied to a case study of access at a London airport. Results are presented in terms of passengers' satisfaction with various access attributes, and the scale deduced for access information indicates the need for better distribution of access information to air passengers.