One of the strengths of the RAF in 1940 was its diversity. The victories of the Germans across Europe had encouraged men from across the British Empire to travel to Britain to join the RAF. In Europe itself, airmen from the countries that the Germans took over or attacked travelled to the UK to try to carry on the fight against the Nazis.
According to the RAF Museum and other sources (https://www.rafmuseum.org.uk/research/online-exhibitions/history-of-the-battle-of-britain/battle-of-the-nations.aspx)
During the Battle of Britain one fifth of Fighter Command’s aircrew came from overseas and 16 nations were represented in its squadrons. A total of 126 New Zealanders, 98 Canadians, 33 Australians and 25 South Africans participated. They were joined by three Rhodesians, a Jamaican, a Barbadian and a Newfoundlander. The Commonwealth countries produced some of the best fighter pilots, including the Australian Flying Officer Paterson Hughes and Flight Lieutenant Adolph ‘Sailor’ Malan from South Africa.
After the fall of France, the RAF welcomed into its ranks exiles from German-occupied Europe. In all, 145 Poles, 88 Czechoslovaks, 29 Belgians, 13 Frenchmen and an Austrian flew in the Battle and many of these proved to be excellent pilots. Though only operational for six weeks, the Polish No. 303 Squadron claimed 126 victories to become the top scoring RAF unit. The most successful RAF pilot, with 17 kills, was Sergeant Josef Frantisek, a Czech national who also flew with ‘303’.
In addition to the different nationalities, there were also different religions in the RAF. Christian, Jewish, Muslims, Sikhs and Hindus all served as part of the RAF.
THE POLISH CONTRIBUTION – 302 AND 303 SQUADRON
The Polish air force was no match for the technically superior Luftwaffe in terms of aircraft. However, the Polish pilots and crews were very good and fought as best they could when Germany invaded Poland in September 1939. Many of the Polish airmen flew to France once Poland was defeated, so that they could continue to fight the Germans. After France also fell in June 1940, approximately 8,400 Polish airmen travelled to Britain, which they now called Wyspa Ostatniej Nadziei or ‘The Island of Last Hope’.
Initially, the British authorities were unsure about how to use the Polish pilots, especially as many of them did not speak any English. Then, in August 1940, it was agreed to form them into two squadrons, 302 and 303 Squadron. (A squadron is a way of organising pilots, ground crew and aircraft into groups – a squadron will contain 12–24 aircraft plus the number of pilots, crew, etc. that are needed to support the activities.)
The Polish pilots had fought the Germans before; they understood some of their tactics in the air and were able to counter them. After the Battle of Britain, the Poles continued to serve in the RAF as part of the PAF (Polish Air Force), including large numbers of ground crew (engineers, etc). They were all offered English lessons, and technical manuals were translated into Polish. By the end of the war in 1945, there were approximately 15 squadrons in the PAF, covering fighter planes, bombers and coastal and special duties, with approximately 14,000 men and women serving in them.