After aborting a landing (a "go around") just above the runway due to wind shear, a B-17 climbs away at a ludicrously steep angle at low speed. In reality, that aircraft would have just stalled into the ground and killed everyone.
Bucky starts the jeep by turning a key near the end. Jeeps had a pedal/button on the floor to engage the starter.
Egan is shown flying as an observation pilot with the 389th Bomb Group, while in reality he flew with the 305th.
At 22:06, as the B17s arrive at the English base, numerous local residents stream on the base near the the landing strips and taxi ways. In one scene, they are actually only feet away from spinning props. While Hanks, et al, were attempting to evoke an emotional setting to demonstrate the Brits' interest and likely even joy, this flies (sorry for pun) in the face of security and safety protocols that would have been at high levels.
When bombers arrive over their target a heavy, multi-layered cloud cover below them can be seen in multiple shots. Yet German flak guns have no problem with covering the bomber group with accurate fire.