From what I gathered the odds won’t good in those things
First it was required to complete 25 missions to be able to go home... 77% of the men who served over there in late 42 and early to mid 43, didn't complete their 25 missions to go home.... they were either killed in the air, shot down over occupied Europe or just lost it from stress and were grounded.
The base I went to school on, RAf Molesworth was home to the 303rd BG. Four of the original B 17s made it to 25 missions and actually thru 50 and 75 missions before being sent home to do War Bond Tours, with their crews. Most other groups weren't so lucky. ALL of their crews who were first sent over in late 42, DIDN'T finish their tours, and ALL were either killed or went down over occupied Europe. Each of the bases mentioned in the Movie or in the Book, were within a 15 to 20 mile radius of Huntingdon. My dad was stationed at RAF Alconbury, just outside of Huntingdon. Many of the bases were still there, held in reserve for NATO. Some like RAF Grafton Underwood and RAF Kimbolton, were gone and torn down in 1963 when we got to England in mid 1963. The war had been over for only 18 years.
Out of towns in the countryside, many groves of trees, you could find pillboxes left over from the war, built during the Battle of Britain, in case the Nazis had invaded England in 1940. The were still finding munitions of bombs that had been dropped in 1940 that had never exploded., ALL over Southern England.
There were many people in the town I lived in off base ( housing was a bear to find), that had lived there during the WAR. There were plenty of WW 1 veterans also all over the neighborhoods. Most of them really liked knowing Americans and having them as friends. A lot of men in their 40s at that time, had been in the RAF and were shot down over occupied Europe, and spent the war in PoW camps.. others I knew were captured at Dunkirk and survived. We could get them to talk about their experiences during WW2, they enjoyed relating it to kids who were interested.
The war was far removed for American kids. NOT so for English kids. There parents and grandparents had lived thru it.
There was plenty of remains all over England left over from the war. We had several factories in Eynesbury were we lived that had been bombed and destroyed during the Battle of Britain by the Luftwaffe. They were never rebuilt and the site still had the brick and stones they were made from, still stacked up after being cleaned up, but left on the property.
Since we lived off base, by law, my youngest brother had to go to the local English Elementary School. They start at 4 years old. The property was all asphalt and brick walls. The remainder of the paint put on the walls that were meant to turn color if the Germans had dropped Gas Bombs to kill the population. The walls from 63 to 66 were still painted from the war...to detect gas.
Everywhere we lived in the shadows of what had happened in England during WW 2. There were still many based left over from WW 2, all just locked up and that's it.. the Nissen Huts, Hangers, Runways, Hard Stands etc were still all there. Molesworth still had the remains of the B17 Junkyard where they would pull parts off of scrapped bombers. There were quite a few still out there in the early to mid 60s, left over from the war 20 years earlier.