Boeing built nearly half of all B‑17 Flying Fortresses produced during World War II

Of these bombers, approximately one-third were lost in combat—4,735 aircraft—highlighting both their extensive use and the dangers faced by crews during daylight bombing raids over Europe. Initially flown without long-range fighter escorts due to beliefs that formation flying would provide sufficient defense against enemy fighters, many missions resulted in heavy losses until escort tactics changed later in the war.

The average life expectancy for a B-17 crew or plane could be as low as eleven missions at certain points in late 1943. Events like 'Black Thursday' saw major losses: out of a force of 229 bombers sent out by Eighth Air Force on one mission alone, sixty were lost outright with additional planes crash landing or requiring significant repairs.

After WWII ended most surviving B-17s were scrapped. Today about one hundred airframes remain worldwide in varying conditions—from operational status to static display or storage—with only a handful still capable of flight. According to Aero Vintage Books’ listings from recent years: three are currently operational (flying), five are undergoing long-term maintenance intended for future flight status again; others are being restored either for operation or static display purposes.

The Commemorative Air Force is among few organizations that maintain an airworthy B-17 and offers public flights during certain seasons; passengers can sit throughout various compartments for short flights lasting around twenty minutes.

Although surpassed numerically by the Consolidated B-24 Liberator—which saw over eighteen thousand examples produced—the B-17 Flying Fortress stands as America’s second most-produced bomber model from WWII. Its manufacturing involved several companies across multiple sites nationwide.

Despite fewer than four thousand units being built for Boeing’s subsequent Superfortress program (B-29), that effort proved more costly than any other American military project during WWII—even exceeding expenditures on projects like Manhattan or Germany’s V‑2 rocket initiative.

Most existing flying examples today come from Lockheed and Douglas builds rather than original Boeings; however many Boeing-built airframes remain preserved as museum pieces globally.