The Condor Shoestring (originally known as the Ast Special and the Mercury Air Shoestring) was a Formula One racing aircraft built by Carl and Vincent Ast to compete in the Cleveland National Air Races in 1949. It was a highly streamlined mid-wing cantilever monoplane with fixed tailwheel undercarriage. The mainwheels were covered with spats.
Made by Condor AeroMercury AirCondor Aero for homebuilding.