William McPherson "Bill" Allen (September 1, 1900 – October 28, 1985) was a U.S. aircraft businessman.
Born in Lolo, Montana, he attended the University of Montana, where he became a member of the Sigma Chi Fraternity. He graduated in 1925 from Harvard Law School, and joined the Board of Boeing Air Transport in 1930 while remaining an employee of his Seattle law firm, Donworth, Todd & Higgins. A year later he joined the Board of Boeing Airplane Company as corporate counsel.
Following the death of Boeing president Philip G. Johnson in 1944, Chairman Claire Egtvedt was tasked with appointing his replacement. Feeling that none of the company's senior engineers had a sufficiently broad background to run the company, he turned to Bill Allen. Considering himself unqualified to run an engineering company, Allen at first declined the offer before finally accepting. Allen served as the president of the Boeing Company from September 1, 1945, until April 29, 1968. He also served as the chairman of the Boeing Company from 1968 through 1972. While he was president of Boeing, he made the famous decision in 1952 to "bet the company", when he authorized construction of the Boeing 367-80 and again when he authorized the launch of development of the Boeing 707. He also participated in launching other planes of renown, among them the Boeing 727, Boeing 737, and Boeing 747.
In 1965, Allen received the Vermilye Medal from The Franklin Institute.
In 1966, Allen asked Malcolm T. Stamper to spearhead production of the new 747 airplane on which the company's future was riding. This was a monumental engineering and management challenge, and included construction of the world's biggest factory in which to build the 747 at Everett, Washington, a plant which is the size of 40 football fields.