MAX, the ship's computer, speaks Bulgarian. When David enters the ship and takes the pilot seat, MAX says "Attention! Crois moi! Assiez Toi! Vnimanie! Oblegni se! Chui me!" which means "Attention! Believe me! Sit down!" in French then "Attention! Sit back! Listen to me!" in Bulgarian.
When MAX and David stop behind the car full of music listeners and asks for directions, MAX (played by Paul Reubens) asks if those were "geeks." "Geek" is exactly how Paul Reubens' most famous character, Pee Wee Herman, was described.
When RALF enters David's room for the first time, its yellow flasher shuts off as soon as the unit stops moving. In the next shot, when the door reopens and Carolyn steps in, RALF's flasher is on again for a split second.
When the alien craft speeds away from the NASA base, its slipstream tears off the roof of a small booth. But the wake also should sweep the people in its flight path down to the ground; it is too close for that not to happen.