N18709 was a Boeing 707-331B delivered new to TWA on 21st May 1966 and served the airline well until being sold to Israeli airline, EL AL on 22nd April 1982, becoming 4X-ATD. It was sold again on 26th January 1989 to Hartland Power Systems Inc as N707HP as an executive transport, but this ownership was short-lived as the Boeing Airplane Co. brought it back in September 1989 for spares use in the military KC-135E conversion programme. Consequently, this aircraft was broken up at Davis-Monthan AFB, Arizona.