LOS ANGELES, Jan. 23 Paul F. Bikle, who oversaw NASA's X-15 program as director of the Dryden Flight Research Facility, died Saturday at a son's home in Salinas, Calif. He was 75 years old and lived in Lancaster, Calif.

Mr. Bikle died of the effects of a heart attack.

Mr. Bikle headed Dryden, which is at Edwards Air Force Base, north of Los Angeles, from 1959 until his retirement in 1971. In his tenure he oversaw programs like the X-15 rocket, which pioneered technology that was employed later to build and fly space shuttles.

He also piloted sailplanes and held the world's altitude record for sailplanes, 46,269 feet, for more than 20 years after setting it in 1961.

Mr. Bikle graduated from the University of Detroit with a degree in aeronautical engineering. He did flight-testing work on the B-29 bomber at Wright Patterson Air Force Base in Ohio in 1940.

Mr. Bikle was chosen to head Dryden after 20 years as an aeronautical engineer with the Air Force. Before joining the National Aeronautics and Space Administration, he was technical director of the flight test center at Edwards Air Force Base.

He is survived by three sons and a daughter.