Boeing's Phantom Eye, a hydrogen-powered, high-altitude, long-endurance demonstrator aircraft, arrived at Dryden in March.
Lockheed built two demonstrator aircraft, designated the Lockheed Model 286, to market to the public (registration numbers N286L and N265LC).
The company decided to offer its fleet of eight demonstrator aircraft for sale in December 2009 at deeply discounted prices.
The demonstrator aircraft will never be armed.
The companies said they planned to study designs and technologies for the new plane, and possibly to design and manufacture a demonstrator aircraft.
Six demonstrator aircraft fitted with 11 seats, wing spoilers and an anti-skid braking system.
Following this study, NASA built a small remote-controlled demonstrator aircraft with a 20 foot (6.1m) wingspan.
Scaled Composites ARES, a demonstrator aircraft built by the company Scaled Composites.
The demonstrator aircraft is a Dimona motor glider, built by Diamond Aircraft Industries of Austria, which also carried out structural modifications to the aircraft.
Bell Eagle Eye: Tilt-rotor demonstrator aircraft for Bell Helicopter (1993)