Fortress

Wally became commander because he was the co-pilot at the time of the Gerbini raid. When Pops was killed along with two waist gunners during the badly damaged raid, Wally was the next highest-ranking crew member and assumed command of the Lucky Lass. The film establishes that leadership passes to the remaining officer, and Wally was thrust into this role five days later when replacements arrived.

Michael got lost because he was flying blind through clouds to avoid flak defenses. When the squadron was ordered to take a roundabout cloud route to reach the target in Messina, Sicily, Michael simply tried to keep sight of the plane ahead rather than using proper instrument navigation. When he emerged from the clouds, the rest of the squadron was gone and he was flying over heavily defended territory, forcing an abort.

The earlier scene shows Wally hungover and too sick to fly, forcing Michael to take controls - establishing his inexperience.

The oil lines became fouled with sand from a recent sandstorm. When Michael took the pilot's chair for a follow-up mission, the sand that had entered the oil system during the storm caused the pressure to climb and engines to lose power. This was discovered only after Michael pushed maintenance chief Caparelli to inspect the aircraft again, revealing the 'gremlins' that had plagued the bomber.

The sandstorm scene shows everyone taking cover while Burt finishes collecting alcohol - the same storm that deposited sand in the oil lines.

The still exploded because Burt rushed to escape the sandstorm without shutting it down. During the fierce storm, Burt was collecting a batch of distilled alcohol but panicked to get to shelter, leaving the still running. This allowed the flammable ethanol to pool on the ground, which later ignited during the next takeoff attempt, destroying the still in a fiery explosion.

Burt earlier explained how the still works - distilling ethanol from aviation fuel - establishing it as highly flammable.

Archie sacrificed himself by taking control of the crippled B-17 when both pilots were overwhelmed. After Wally was killed by flak and the plane was badly damaged with engines failing, Archie left his position to help Michael fly. His parachute was already destroyed in the chaos, so he stayed in the pilot's chair to guide the damaged bomber toward Malta, allowing the remaining crew to bail out. He and the navigator perished when the aircraft disintegrated.

Wally was killed by flak (anti-aircraft fire) as the Lucky Lass attempted to escape Rome. After their bomber was damaged when a hit B-17 clipped their stabilizer, Michael and Wally struggled to regain control. Just as they pulled out of the spin, a barrage of flak knocked out another engine and obliterated Wally in the cockpit. He died mid-sentence, telling Michael to take the plane home.

The Rome mission was described as particularly dangerous, with heavy defenses surrounding the city.

Oliver was killed by a flak round while in the waist position. After Wally was killed and the bomber was limping away from Rome under heavy ground fire, Tom checked on Oliver, who initially said he was OK. However, another flak round struck the waist section and killed Oliver. He was one of the two new waist gunners who had just joined the crew.

The crew blamed Michael because both major incidents occurred when he was at the controls. First, he got the bomber lost on a milk run, then shortly after he took the pilot's chair for the first time, the oil pressure crisis forced another abort. The crew's superstition led them to view him as unlucky, even though the oil problem was later proven to be a mechanical issue caused by sand, not his piloting.

Michael's earlier standoffishness at the party - not drinking with the men - already showed he hadn't earned their trust.

The crew dubbed Michael "O'Schmidt" to mark him as an honorary Irishman after he took responsibility for Charlie's theft of liquor from the officers' club. When Charlie was caught stealing liquor for a promised celebration, Michael explained the plane's mechanical issues and accepted blame for not giving explicit orders. Colonel Shay pretended to believe him and let Charlie off. That night, the crew celebrated by christening Michael "O'Schmidt" as a sign of acceptance.

The film establishes that airmen were required to complete 25 combat missions before they could be rotated home. This was standard USAAF policy at the time. However, the opening narration reveals the brutal reality: only about two in ten crews would survive to reach that target, making the 25-mission requirement a grim lottery rather than a sure thing.

Michael wanted to transfer because he felt responsible for the failed milk run and sensed the crew's hostility toward him. After the mission, he overheard disparaging remarks about himself while approaching the crew's tent and decided the timing wasn't right to address it. He told Wally he planned to apply for a transfer, believing he'd lost the crew's trust.

The party scene showed Michael refusing to drink with the crew, already setting him apart as an outsider.

The Lucky Lass was grounded because of the recurring mechanical problems - first the lost milk run, then the oil pressure failure - while the larger squadron was decimated because fighter protection was diverted during their next mission. Enemy fighters appeared over the target and inflicted heavy losses on the unprotected bombers. With the Lass grounded and other aircraft destroyed, some crew had to be mixed into other flights for subsequent missions.

Charlie was caught because he was stealing liquor to honor a promise to Al for a celebration on his safe return. He was caught by quartermaster Monroe while taking the liquor from the officers' club. Charlie faced potential court-martial, but Michael intervened by explaining the mechanical issues and accepting responsibility for not giving explicit orders about the celebration.

Michael became a flight commander because he survived his tour and was promoted. After the Rome mission where Wally was killed and the crew suffered heavy losses, Michael eventually completed his required missions. By the epilogue, he had been promoted to flight commander and was leading a new bomber crew at Navrin. The film ends with a new replacement arriving, showing the cyclical nature of war where leadership is constantly tested and turnover is constant.