Josef František DFM & Bar (7 October 1914 – 8 October 1940) was a Czechoslovak fighter pilot and Second World War fighter ace who flew for the air forces of Czechoslovakia, Poland, France, and the United Kingdom.
He was the highest-scoring non-British Allied ace in the Battle of Britain, with 17 confirmed victories and one probable, all gained in a period of four weeks in September 1940.
František was a brilliant pilot and combatant but had frequently breached air force discipline first in Czechoslovakia, then in France and finally in Britain.
The RAF found it best to let him patrol alone, a role in which he was highly successful.
He was killed in a crash in October 1940 in the final week of the Battle of Britain.