This episode brings us Weasel as the pilot of a commercial airplane line, which transports people who want to migrate to their desired destinations. I know, it sounds silly, but the episode isn't that bad, actually.
Weasel's mission is to protect the people in the plane from the beavers below, in the water, who have decided to build dams high enough to attack the airplane, and stop people from migrating.
Other things worth mentioning would be the little documentary movie Weasel shows the passengers during the flight (hilarious), and the case of the man who goes insane because he can't open his bag of peanuts! Not to mention the Red Guy as a stewardess, and how Weasel has to assist the birth of every female passenger on board!
Over all a good episode. The plot might seem a little off, but compared to some earlier episodes (from the first season, especially), it's still good.