Can you use a laptop on an American Airlines flight?

Yes, of course. You can use laptops on any airline. But only during the flight, after the plane has reached cruising altitude, and the flight attendants have announced that it's "OK to begin using approved electronic devices" (laptops, video games, MP3 players, etc.). You cannot use any electronic device during take-off or landing. If you do, it's no big deal, but the flight attendant will tell you to put it away, and you'd better do so if they ask. If you disobey any command they give you, you're breaking Federal Law.