According to "The Making of The Philadelphia Experiment", the Wendover, Utah air base used in the film's climactic fire sequence was where the Enola Gay was outfitted for its historic flight in 1945.
The movie is set in Philadelphia. However, the ships used were at Patriots Point, Charleston South Carolina. The aircraft carrier, destroyer, and submarine are docked in the same positions as the movie.
Back in 1980, AVCO Embassay Pictures asked John Carpenter, who serves as an executive producer on this film to both write and direct this film after the success of Halloween (1978) and The Fog (1980). However, Carpenter showed them Escape from New York (1981) (which he wrote years earlier) and they did that instead.