Designed and produced originally by Ceskoslovenske Zavody Automobilove A Letecke, under which heading all post-World War II aviation activity in Czechoslovakia was first combined, production of the L-40 Meta-Sokol was continued by Letecky Narodni Podnik (Let) after this manufacturer was established at Kunovice in the mid-1950s. A four-seat cabin monoplane of all-metal construction, suitable for training or sporting use, the Let L-40 was of low-wing configuration and incorporated unusual 'reversed-tricycle' landing gear. All three units retracted, but the short-wheel-base tailwheel unit was mounted beneath the cabin so that the fuselage was almost horizontal when the aircraft was on the ground. As first flown in 1956 the L-40 was powered by a 104kW Walther M 332 inline engine, but series aircraft were available with either this engine or a 78kW Walther Minor 4-III. When production ended in 1961, 200 L-40s had been built.