Joey Cramer as David Scott Freeman

Paul Reubens as Max (voice)

Veronica Cartwright as Helen Freeman

Cliff DeYoung as Bill Freeman

Sarah Jessica Parker as Carolyn McAdams

Matt Adler as Jeff (16 years)

Howard Hesseman as Dr. Louis Faraday

Robert Small as Troy

Jonathan Sanger as Dr. Carr

Richard Liberty as Mr. Howard

Raymond Forchion as Detective Banks

Cynthia Caquelin as Woman Officer

Ted Bartsch as Night Guard Brayton

Brigid Cleary as Technician #2

Michael Strano as Technician #3

Parris Buckner as Scientist #1

Robyn Peterson as Scientist #2

Philip Hoelcher as NASA Officer

Julio Oscar Mechoso as Hangar Guard #1

Butch Raymond as Hangar Guard #2

Chase Randolph as Lieutenant King

John Archie as Agent #1

Tony Calvino as Agent #2

Rusty Pouch as Gas Station Attendant

Robert Goodman as Tourist Man

Peter Lundquist as Newscaster #1

Jill Beach as Newscaster #2

Kenneth Ian Davis as Kid in Mustang

Arnie Ross as NASA Technician

Fritz Bronner as NASA Technician

Albie Whitaker as Jeff 8 year

Tony Tracy as Observation Guard