Leduc began designing athodyds (ramjets) in 1929 at Argenteuil, as well as experimental aircraft in which to test them. The L.010-1, started 1937 and completed 1945, was first purely athodyd-powered manned aircraft to fly. Followed by L.010-2 and similar L.016-1 in 1951. All air launched from Languedoc mother plane. In 1953-1954 appeared the L.021 -01 and -02, and plans existed for a swept-wing aircraft with Atar 101 turbojet engine for independent take-off and an 0.22 supersonic fighter.