The Letov Š-22 (also designated as the S-22 or Š.22) was a single-engine, single-seat fighter prototype developed in Czechoslovakia during the mid-1920s. Designed by Alois Šmolík, who served as the technical director and chief designer at Letov, the aircraft was an experimental departure from the company's standard biplane fighters of the era. Šmolík, who had been designing aircraft and gliders since 1910, sought to create a high-altitude fighter utilizing an all-metal construction and a parasol-wing monoplane layout, a configuration heavily influenced by the French Dewoitine designs of the period.
The aircraft was manufactured at the Letov factory (Vojenská továrna na letadla Letov) located in the Letňany district of Prague. Letov had been established in 1918 by the Czechoslovak Ministry of Defense, originally as a facility for repairing World War I trophy aircraft before evolving into a primary producer of indigenous military aircraft, such as the Š-1 reconnaissance biplane. The Š-22 prototype was constructed and flown in March 1926. However, the experimental design proved unsuccessful; by the end of April 1926, Letov determined the aircraft was not viable and ceased all further development.
Technically, the Š-22 was powered by a single Škoda L W-12 water-cooled piston engine, which featured three banks of four cylinders. This engine, a derivative of the Hispano-Suiza 12Gb with a modified lower crankcase, produced between 336 and 340 kW (450 hp) and drove a two-blade propeller. The aircraft's physical dimensions included a wingspan of 10.18 meters, a length of 7.65 meters, and a wing area of 15.59 square meters. It had an empty weight of 934 kg and a gross weight of 1,285 kg. For armament, the design called for two synchronized 7.70 mm Vickers machine guns firing through the propeller arc, though these were never flight-tested.
Because the project was abandoned so quickly, the Š-22 never entered service with the Czechoslovak Air Force and saw no combat or operational use. No series production ever occurred, leaving the single prototype as the only example built. Today, no airworthy examples or museum pieces exist, as the airframe was likely scrapped. While a minor footnote in aviation history, the Š-22 illustrates the early efforts of the Czech aviation industry to innovate with monoplane designs during the interwar period.