Sam Hall: Look, I got every question right on the final, and the only reason Mr. Spengler failed me is because I didn't write out the solutions.
Jack Hall: Why not?
Sam Hall: I do 'em in my head.
Jack Hall: Did you tell him that?
Sam Hall: I did. He said he didn't believe me. He said that if he couldn't do them in his head, then I must be cheating.
Jack Hall: Well, that's ridiculous! How can he fail you for being smarter than he is?
Sam Hall: That's what I said.
Jack Hall: You did? How did he take it?
Sam Hall: He flunked me, remember?
When Jack is briefing the President, he draws a line on a map of the U.S. and tells the President to have everybody south of that line evacuated. The shape of the line changes between shots.
Before the film was released, N.A.S.A. sent a memo out to all of its employees stating that they were not allowed to comment on the likelihood of the events portrayed in this movie.