This set of toy airplanes and spacecraft includes several experimental aircraft and the Space Shuttle Enterprise, NASA's test vehicle for Space Shuttle approach and landing tests. The vehicles represented in this toy set illustrate different designs and technologies with potential for use in spaceflight.

X vehicles were experimental craft created to test new designs and technologies. The high speed research aircraft X-15 tested thermal heating, high speed control and stability, and atmospheric re-entry. Some X-15 flights reached outer space. The USAF planned the X-20 to be the first orbital glider, but the program was cancelled. The X-20's design included ceramic heat-resistant material, a technology later used on Shuttle orbiters. The X-24A was designed to test a lifting-body (a vehicle where the craft's fuselage itself provided lift). The X-38 Crew Return Vehicle (CRV) was to be an unpiloted, air-dropped craft that used a para-glider configuration for landing crew returning from the International Space Station.

Valerie Neal, the National Air and Space Museum curator who oversees artifacts from the Space Shuttle program, donated the toys to the National Collection in 2003.