By mid-1944 the 8th Army Air Force in the UK had replaced their entire force every six months due to losses. It's incredible they could take such losses and fight on like they did. The Mighty Eight suffered 4,145 of the total 10,561 American air losses in Europe during WWII. On their worst mission they lost 26% of the bomber force in one day.
"On 2nd Schweinfurt/Mission 115 (14th October) as part of Pointblank, fifty-nine Flying Fortresses were shot down over Germany, one ditched in the English Channel on the return flight, five crashed in England, and twelve more were scrapped due to battle damage or crash landings, a total loss of seventy seven B-17s. 122 bombers were damaged to some degree and needed repairs before their next flight. Out of 2900 men in the crews, about 650 men did not return, although some survived as POWs. Five were killed and forty-three wounded in the damaged aircraft that made it home, and 594 were listed as Missing in Action. Only thirty-three bombers landed without damage.
A total of 77 aircraft destroyed - out of a force of 291."