Explorers

A boy obsessed with '50s sci-fi movies about aliens has a recurring dream about a blueprint of some kind, which he draws for his inventor friend. With the help of a third kid, they follow it and build themselves a spaceship. Now what?

Explorers is a 1985 adventure romance movie directed by Joe Dante, starring Ethan Hawke, River Phoenix, Bobby Fite. It holds an IMDb rating of 6.4/10 from 25,509 votes and runs 1h 49m.