In June 1944, as the Liberation of Europe was about to commence, the Royal Air Force included in its Order of Battle a total of 57 Squadrons "formed from men who had, by one means or another, escaped from occupied countries and made their way to British Territory - in other words, men cast in the heroic mould." The quote is from "The Right of the Line" by John Terraine.
Those 57 Squadrons came from the following Countries:
Yugoslavia 1 Sqn
Belgium 2 Sqns
Greece 3 Sqns
Holland 3 Sqns
Czechoslovakia 4 Sqns
Norway 4 Sqns
Poland 13 Sqns
France 27 Sqns