The Lancaster Language Testing Research Group was commissioned in 2006 by the European Organisation for the Safety of Air Navigation (Eurocontrol) to conduct a validation study of the development of a test called ELPAC (English Language Proficiency for Aeronautical Communication), intended to assess the language proficiency of air traffic controllers. As part of that study, Internet searches for other tests of air traffic control identified a number of tests but found very little evidence available to attest to the quality of these tests. Therefore, it was decided to conduct an independent survey of tests of aviation English, since the consequences of inadequate language tests being used in licensing pilots, air traffic controllers and other aviation personnel are potentially very serious. A questionnaire was developed, based on the Guidelines for Good Practice of the European Association for Language Testing and Assessment (EALTA, 2006), and sent to numerous organizations whose tests were thought to be used for licensure of pilots and air traffic controllers. Twenty-two responses were received, which varied considerably in quantity and quality. This probably reflects a variation in the quality of the tests, in the availability of evidence to support claims of quality, and in low awareness of appropriate procedures for test development, maintenance and validation. We conclude that we can have little confidence in the meaningfulness, reliability, and validity of several of the aviation language tests currently available for licensure. We therefore recommend that the quality of language tests used in aviation be monitored to ensure they follow accepted professional standards for language tests and assessment procedures. (Contains 7 tables.)