American heavy bombers of the time carried an 8,000-pound bomb capacity and the four-engine planes were armed with 11 machine guns and strategically placed armor plating. B-17s cruised at about 27,000 feet, but weren’t pressurized. At that altitude, the air is thin and cold — 60 degrees below zero. Pilots and crew relied upon an onboard oxygen system and really warm flight suits with heated shoes. Despite having the ability to take a lot of punishment, and despite carrying a number of heavy gun turrets, B-17s were still very vulnerable to enemy fighter attacks. The US Army Air Corps tried to alleviate the planes vulnerabilities by putting B-17s in staggered formations which allowed bombs to be dropped while many planes could cover the inevitable defensive gaps of other aircraft with overlapping fields of fire.
The downside to this alignment was that individual planes could not take evasive maneuvers (they’d risk damage from friendly bombs or machine gun fire), and stragglers were completely open to attack by enemy aircraft. Despite the inherent risks involved with these tactics men continued to do their duty and their bravery is completely without question.
The strategic bombing campaign during WW2 cost 160,000 Allied airmen their lives and 33,700 planes were lost in the European theater alone.