Along with the B-17, the B-24 formed the backbone of the Allies' air war over Europe. In a strategic campaign, the airplanes and their crews attacked factories, railroads, harbors and — as the war progressed — cities in Germany, Italy and occupied France. The bombings curbed Germany's manufacturing capabilities and wore down its citizens' morale.

Employee training was a constant process at Willow Run. In on-site classrooms, newly hired workers sat through orientation lectures on the aircraft industry in general, the B-24's specific importance to the war, and the dire consequences should the Allies lose the fight. Specialized employees — riveters, for example — received training in these classrooms as well.

Ford struggled to get Willow Run running at full potential. The government's constant design changes to the B-24 were particularly troubling. Ford's production methods depended on a "fixed" design — each design modification required expensive and time-consuming updates to the assembly line. As the problems continued into 1943, critics took to calling the plant "Will it Run."

Willow Run's problems came under a microscope in April 1942 and again in February 1943, when Senator Harry S. Truman visited the plant. Truman headed a presidential committee charged with eliminating wartime production waste, and Willow Run's struggles worried him. Ford president Edsel Ford and his team explained the difficulties with design changes. Truman was unimpressed — he didn't want excuses, he wanted finished bombers.

With so many young men drafted into the armed forces, Willow Run's workforce was unusually diverse for its time: African Americans, whites, older people, younger men unable to serve in the military, and — most notably — women. Approximately one-third of the plant's assembly line workers were female. At its peak, Willow Run employed more than 15,000 women — some 35 percent of its total staff.

Riveting was an essential craft at Willow Run. Each completed B-24 contained more than 300,000 rivets in more than 500 sizes. The skilled women who accomplished this work — at Willow Run and elsewhere — inspired the symbolic "Rosie the Riveter" character. Today "Rosie" remains a feminist icon and a powerful reminder of women's contributions to the American economy.

With the pressures of wartime production schedules — and the sense that victory itself depended on their efforts — Willow Run's employees needed occasional relief from their burdens. Baseball games at the on-site recreation field took away some of the strain during off-duty hours. Factory golf and bowling leagues provided additional opportunities for relaxation.

Ford officials looked for every efficiency they could find in B-24 production. Some riveted parts were replaced with cast pieces to simplify and speed their manufacture. Most controversial was Ford's decision to replace soft metal dies — thought to be gentler on aluminum airplane components — with hard steel dies. Steel dies proved more precise, longer lasting, and perfectly safe.

At last Willow Run hit its stride in 1944. That April, employees in two nine-hour shifts, working six days a week, produced 453 airplanes in 468 hours — a production rate equal to one finished B-24 Liberator every 63 minutes. Charles Sorensen's brash "one plane every hour" claim was no longer an empty boast. Willow Run and its workers met their goal.

In addition to complete airplanes, Willow Run produced "knock-down kits" that were shipped to Douglas Aircraft's plant in Tulsa, Oklahoma, and Consolidated Aircraft's plant in Fort Worth, Texas, for final assembly. Each kit — consisting of 80 percent of the parts for a finished B-24 — was shipped via two tractor-trailers. Willow Run workers built 1,893 kits over the course of the war.

Employees at Willow Run celebrated the completion of their 6,000th airplane in September 1944. Ford now planned to build 650 planes each month — one every 45 minutes. But just when that milestone seemed possible, the government drastically cut its order for B-24s. The war's focus was shifting from Europe to Japan, where more-advanced B-29 bombers were needed. They would be built elsewhere.

Workers at Willow Run built a staggering 8,685 B-24 bombers — 6,792 complete planes and 1,893 knock-down kits -- by the time the last one was finished on June 28, 1945. No one had ever manufactured airplanes on such a scale before. Ford proved that even the most complicated military machines could be built using the techniques it pioneered with the Model T.