X-24B - The X-24B made two precise landings on the main concrete runway at Edwards which showed that accurate unpowered reentry vehicle landings were operationally feasible. Pilots on these missions would fly steep descents and then perform a "flare out" maneuver at high speeds to make a 200 mph landing. These missions represented the final milestone in a program that helped write the flight plan for the NASA Space Shuttle program. source: Wikipedia
The Hughes H-4 Hercules (also known as the "Spruce Goose"; registration NX37602) is a prototype heavy transport aircraft designed and built by the Hughes Aircraft company. The aircraft made its only flight on November 2, 1947, and the project never advanced beyond the single example produced.