Stefan Bastyr (August 17, 1890 – August 6, 1920) was a Polish aviator and military pilot, one of the pioneers of the Polish aviation. He is credited with the first military flight in the history of the Polish Air Force on November 5, 1918, almost a week before Poland officially regained her independence, at the opening stages of the Polish-Ukrainian War.
Initially he was a military pilot in Austria-Hungary during the World War I. From February 1916 he served as an observer in Flik 10 reconnaissance squadron on the eastern front, from December 1917 in Flik 12D on Austro-Italian front. In 1918 he himself trained as a pilot and was assigned to Flik 37P from June 1918. He undertook about 100 sorties during the war and scored at least 1 air victory on June 4, 1916.
In the Polish Air Force, he took part in the Battle of Lwów (1918). He died in an aircrash of Fokker D.VII in Lviv (probably due to a hear failure) during the Battle of Lwów (1920) and is buried at the Łyczaków cemetery in Lwów (modern Lviv).