Frank Wilson

Ken Berry

Liz Bartlett

Sandy Duncan

General Stilton

Harry Morgan

Link

McLean Stevenson

Mr. Stallwood

Roddy McDowall

Earnest Ernie

Jesse White

Dr. Winger

Alan Young

Dr. Heffel

Hans Conried

1st E.R.L. Expert

Roger Price

Jake

Ronnie Schell

1st NASA Scientist

Gil Stratton

Capt. Anderson

James Hampton

Presiding Judge (uncredited)

Sorrell Booke

Col. Woodruff

Howard Platt

Charlie Olympus

William Prince

Andrew Duncan

Weasel

Ralph Manza

Honest Harry

Tom Pedi

Officer

Hank Jones

Red

Roger Pancake

Dydee Guard

Rick Hurst

Mr. Smith

John Alderson

Omar

Tiger Joe Marsh

NASA Executive

Arnold Soboloff

1st Soldier

Mel Carter

Farmer

Dal McKennon

Farmer's Wife

Alice Backes

Sandwich Man

Henry Slate

2nd E.R.L. Expert

Jerry Fujikawa

Dydee Driver

Jim Begg

Bailiff

Pete Renaday

Technician

Rich Sorenson

Technician

Rickie Sorensen

Army Engineer

Tom Jackman

Sarasota Slim

Fred L. Whalen

Sucker

Joe Medalis

2nd NASA Scientist

Jana Milo

Additional Voices (voice) (uncredited)

Jackson Bostwick