*Research and development/USA/Lockheed Martin WP-3C/WP-3D Orion
*Research and development/USA/Scaled Composites Model 281 Proteus
*Research and development/USA/Lockheed Martin NP-3D Orion
*Research and development/UK/BAE Systems Jetstream research and development variants
*Research and development/UK/British Aerospace BAe 146-301 Atmospheric Research Aircraft (ARA)
*Research and development/Russian Federation/Myasishchev M-55
*Research and development/UK/Hawker Siddeley Andover/HS 748 QinetiQ testbed variants
*Research and development/UK/BAC 1-11 testbed variants
*Research and development/USA/Lockheed Martin NP-3C 'Hairy Buffalo' variant
Research and development/USA/Boeing 757-200 F/A-22 avionics testbed variant
*RESEARCH AND DEVELOPMENT/Australia/Raytheon Beech King Air 350B Ingara testbed
RESEARCH AND DEVELOPMENT/USA/Douglas C-54G Lockheed Martin airborne laboratory variant