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)