Turret gunner Jonathan (Casey Siemaszko) made a big deal about being the Captain's (Kevin Costner) good luck charm on twenty two prior bombing flights, so this would obviously be the twenty third. However several references to the flight later state that it's the twenty fourth; in fact, one of Jonathan's sketches is rendered as the 24th.
The Pilot's cigar keeps changing length from short, around three inches, to long, about six inches, and back again.
The plane appears to be flying a mission at night or in very heavy overcast. The Eighth Air Force flew Daylight missions over Europe for Precision Bombing. Night Time missions were flown by the RAF Bomber Command. if the weather was heavily overcast, the mission would have been scrubbed.
The radio Operator (?) tells the pilot they are low on fuel but might make it with a good tailwind. He then suggests lowering the landing gear while they are far away from base. Lowering the landing gear would have caused drag that would have not only slowed the plane down unnecessarily but would have burned more of the already low fuel.
The crew of a B-17F was 10 men. Pilot, Co-Pilot, Bombadier, Navigator, Radio operator, Top Turret gunner/Flight Engineer, Left Waist Gunner, Right Waist Gunner, Ball Turret/Belly Gunner, and Tail Gunner. When the captain is checking on the crew, he does NOT receive a report from the Navigator or the Tail Gunner. Ten crew are not on the plane.
The crew speaks of the 24th mission that they are going on as the last one before they are rotated out. In the Eigth Air Force's B-17 Bomber force, 25 Missions was the initial cut off for combat missions. This was later revised upward to 30 and 35 missions as the survival odds improved for the crews due to long-range escorts (P-51's) arriving and the near decimation of the Luftwaffe. The 24th mission would have been the NEXT to last mission.
The radio operator is informing the pilot about the fuel levels and distance to the airfield. These two operations would have been the responsibility of the Flight Engineer or Pilots (fuel) and the Navigator (distance and heading) NOT the radio operator.
Although the plane's altitude wasn't mentioned during the German air attack, B17 bombers would routinely fly at 20,000 ft. or higher during bombing missions. If that was the case, the crew would need oxygen masks, heated suits and gloves to survive but none of them are seen wearing them at any time.