Explorers (1985) on Netflix

This adventurous space tale stars Ethan Hawke and young star River Phoenix as misfit best friends whose dreams of space travel become a reality when they create an interplanetary spacecraft in their homemade laboratory. Ben Crandall is a young visionary who dreams of space travel while watching late-night B monster movies, pouring over comic books, and playing Galaga in the confines of his bedroom. But one night he has a vivid dream of flying over a space-like circuit board and shares his visions with his best friend Wolfgang, a young scientific genius who is able to translate his dreams into a complex computer program that actually works. With the help of their new friend, they create a homemade spacecraft and embark on a secret adventure to another galaxy where they find that things are not always as different as they seem.