I notice that a lot of the references compare the RAF to the USAAF bombers.
The RAF Lancaster had a large bomb bay area and could carry a normal load of 14,000lb - about twice the amount of the B17 Flying Fortress.
But the USAAF Fortress flew at a much greater ceiling (35,000ft as compared to the Lanc at 21,000ft) and therefore outranged most of the Luftwaffe fighter aircraft and anti-aircraft guns which couldnt match it.
The Lancaster was used for carpet bombing (many bombs over a wide area) whereas the Fortress was used for 'precision bombing' (one bomb in every load coming within five miles of its target) :-)
Huge numbers of both types were shot down on raids over occupied Europe and many aircrew were killed.
But in general, the song refers to airborne forces of the army, not the airforce.