Although Pan Am also operated the rival Douglas DC-8, it was the Boeing 707 which became the mainstay of the airline's long-haul network. N412PA (c/n 18842) was the 421st Boeing 707 off the Seattle production line, having first flown on 30th April 1965. In keeping with the airline's naming policy, it was dubbed 'Clipper Empress of the Skies' and remained with Pan Am until June 1978 when the leasing company ATASCO bought several of the airline's B707s for onward lease, with this particular model moving to THY - Turkish Airlines as TC-JBU. In February 1985 the aircraft became a resident at Davis-Monthan in Arizona when the Boeing Military Airplane Company bought the B707 for use in the KC-135E program.