Between the wars the RAF was responsible for mail and armed forces services, but saw little military action. Of particular note was 1928's air evacuation of civilians from Afghanistan, the first operation of its kind. This period also the formation of the major flying schools that still provide its service personnel.
Perhaps the defining moments of the RAF's existence however, came during the Battle Of Britain. Over the summer of 1940 the RAF held off the Luftwaffe in an air war, perhaps the first of its kind, contributing immensely to the delay of Operation Sea Lion, and helping to turn the tide of World War II.
There were also a RCAF (Canadian), RNZAF (New Zealand)...
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