The U.S. entry into the war in December 1941 rapidly increased the need for the XP-47B and work on the plane progressed quickly. In June 1942, the Army took delivery of its first P-47Bs. They soon placed an order that required Republic Aviation to quadruple the size of their factory and build three new runways at the Farmingdale, New York factory. Eventually this proved inadequate, and in November 1942, the Army authorized the construction of a new factory adjacent to the Evansville, Indiana airport.