McDonnell Aircraft Co. formed on merger 28 April 1967. MAC appointed foster-parent to USMC Harrier 1970, and further work by MCAIR led to AV-8B Harrier II and other variants produced in partnership with British Aerospace. Navy T-45 Goshawk was joint programme British Aerospace and Douglas but transferred 1989-91 to MCAIR St Louis. USAF FX requirement won by F-15 Eagle (27 July 1972), total 1,034 plus 191 made by Mitsubishi plus 200 (minimum) F-15E. Navy VFAX requirement won by partnership with Northrop producing F/A-18 Hornet (18 November 1978), total 1,157 (minimum). Many projects but hit by cancellation A-12 Avenger and non-selection YF-23A, so big effort to win Navy A-X (teamed with Vought) or Air Force MRF (multi-role fighter).