At the start of the movie, Maverick and Goose see a Russian MIG harassing their wingman. They're not allowed to fire first, so Maverick decides to, "have some fun with him." His idea of "fun" is flying upside-down right above the enemy plane. When the Russian looks up, Maverick gives him the bird, and Goose takes a Polaroid photo to commemorate the moment. The MIG pilot promptly flies away, thoroughly freaked out by the crazy stunt.
When Maverick does a fly-by that causes Air Boss Johnson to spill his coffee on himself, first after Maverick defeats Jester then after the Final Battle.
"Goddamn that guy."
After one of Maverick's many stunts, Goose is spazzing out and asks Maverick what he thinks of Goose learning to be a truck driver after they get kicked out of the Navy. Goose considers this career option based entirely on the fact that he saw a commercial for a truck driving school on TV.