A U.S. Navy Lockheed T2V SeaStar jet piloted by Captain Dale Heath (Efrem Zimbalist Jr.), with an enlisted man (Troy Donahue) as a passenger, runs into trouble as soon as it is in the air. Both Heath's radio and his navigation system become disabled, with no way to correctly determine their altitude. At the same time, a Douglas DC-7 airliner piloted by veteran Dick Barnett (Dana Andrews), is carrying a full load of passengers, each with their own worries and problems to deal with.