United Airlines Flight 736 was a daily U.S. transcontinental passenger flight operated by United Airlines that crashed on April 21, 1958, following a mid-air collision. The aircraft assigned to Flight 736, a Douglas DC-7 airliner carrying 47 persons, was flying at cruise altitude above Clark County, Nevada, en route to a stopover at Denver, Colorado, when it was struck by a United States Air Force fighter jet crewed by two pilots. The collision occurred at 8:30 a.m. in clear weather within a major commercial airway; both aircraft fell out of control from 21,000 feet (6,400 m) and crashed into unpopulated desert terrain southwest of Las Vegas, Nevada..