"Captain Robert Morgan's crew flew 29 combat missions with the 324th Bomb Squadron, all but four in the Memphis Belle."
further:
"The aircraft was then flown back to the United States on 8 June 1943, by a composite crew chosen by the Eighth Air Force from those who had flown combat aboard, led by Capt. Morgan, for a 31-city war bond tour. Morgan's original co-pilot was Capt. James A. Verinis, who himself piloted the Memphis Belle for one mission. Verinis was promoted to aircraft commander of another B-17 for his final 16 missions and finished his tour on 13 May. He rejoined Morgan's crew as co-pilot for the flight back to the United States."
So cross-platform missions were apparently not uncommon at that time and indeed post war. However, mission commander seniority probably also played some role else why would one particular aircraft be named Memphis Belle by a merely part-time mission commander?
As an example of a contrasting situation: my own pilot (squadron CO) and his crew had our names stenciled on one aircraft (NH-601 or maybe it was 611… memory not so good anymore) but I rarely flew with the entire four-man crew or for that matter, in that particular aircraft. So I assume it's most probably not a one-to-one correspondence and instead the aircraft a crew flies is determined by wartime contingencies and general aircraft availability.
am i surprised? not really. info was some what garbled back then as the lines of communication were not always clear and concise...plus its all about proper PR....what would seel the most bonds and endear the hearts of the folks at home. its not the first instance and i am sure wont be the last.
Another B-17F, 'Hell's Angels', also completed 25 missions before the 'Belle', in May 1943. After 43 missions, it was autographed all over the airframe and returned to the USA.