Watch the Skies.

When a small starship crashes to earth, it is not a monster or alien overlord that emerges, but a teenage boy who has run away from home - a home on the far side of the galaxy. He is rescued from capture by the children of the same military leaders who are trying to catch him. Together, the kids must help their new alien friend repair his space ship from parts left behind by other alien explorers and escape before he is caught by the soldiers and studied by the scientists for the rest of his life.