Michael Caine as Brad Crane

Katharine Ross as Capt. Helena Anderson

Richard Widmark as Gen. Thaddeus Slater

Richard Chamberlain as Dr. Hubbard

Olivia de Havilland as Maureen Schuester

Ben Johnson as Felix

Lee Grant as Anne MacGregor

José Ferrer as Dr. Andrews

Patty Duke as Rita

Slim Pickens as Jud Hawkins

Bradford Dillman as Maj. Baker

Fred MacMurray as Maj. Clarance Tuttle

Henry Fonda as Dr. Walter Krim

Cameron Mitchell as Gen. Thompson

Christian Juttner as Paul Durant

Morgan Paull as Dr. Newman

Alejandro Rey as Dr. Martinez

Don 'Red' Barry as Pete Harris

Elizabeth Rogers as Woman Scientist

Doria Cook-Nelson as Mrs. Durant

Robert Varney as Mr. Durant

Ernie F. Orsatti as Duty Officer

Patrick Culliton as Sheriff Morrison

John Furlong as Cameraman

Chris Petersen as Hal

Jerry Toomey as Eddie

Barbara Costello as Receptionist / Nurse

Jenifer Taurins as Nurse

David Himes as Radioman

Mara Cook as Secretary

Joey Eisnach as Bee Boy

Stephen Powers as Radarman

Chris Capen as Lieutenant

Tony Haig as Officer #2

Bill Snider as Radarman #2

George Simmons as Nurse

Arell Blanton as Sergeant

Trent Dolan as Radio Sergeant

John Williams as Launching Officer

Steven Marlo as Pilot #1

Phil Montgomery as Mechanic

Jim Galante as Doctor

Frank Blair as Self

Marcia Nicholson as Captain

Arthur Space as Engineer

Chuck Hayward as Standby Engineer

Glenn Charles Lewis as Chemical Warfare Guard

Art Balinger as Radio Announcer

Michael Sheehan as Airman #1

Howard Culver as Airman #2

Buzz Barbee as Briefing Guest (uncredited)

Ken Clayton as Dr. Moore (uncredited)

Marneen Fields as Train Passenger (uncredited)

Bob Harks as Townsman (uncredited)

Mike Johnson as Burning Man (uncredited)

Jack Krupnick as Train Passenger (uncredited)

Lawrence Moran as Colonel's Son (uncredited)

Monty O'Grady as Briefing Guest (uncredited)

John Otrin as Wild Lines (uncredited)

Leoda Richards as Briefing Guest (uncredited)

Norman Stevans as Briefing Guest (uncredited)