Continuity mistake: When Homer and Marge are on the plane, they both have seat belts on. However, when Marge gets up to run up and down the plane, both seat belts have disappeared.
Continuity mistake: When Moe gets bitten by the snake in the cash register, he has bites all over his hand. But in the next shot when Barney sets him on fire, all the bite marks are gone.
Continuity mistake: When Homer is kicked out of Moe's the window behind Homer suddenly opens so Moe can throw the record out.
Continuity mistake: When the plane takes off without them, you see that the Simpsons are only carrying 2 bags and 2 suitcases. But when it cuts to them un-packing in the house, there are 5 suitcases.
Continuity mistake: When the snake from the cashier bites Moe, the bites on his arm never change and only remain in the one spot even though the snake bit several different spots on his arm.
Continuity mistake: In the scene in the airport bar, two pilots sitting next to each other have brown and gray hair, respectively. When they stand up, the hair has switched colours.
Continuity mistake: On the plane, where Marge is starting to act up due to her Fear of Flying, Homer and Marge's seat-belts have mysteriously disappeared.
Answer: Willy referred to an encounter he believed he had with actual aliens, while Wiggum thought he was referring to the arcade game.