Plot hole: Frankie makes reference to fear of fire early in the movie in the scene with all the guests arriving at the hotel. And in the scene in the local village with the monster festival, a single match is used to send him on a rampage. But throughout scenes in the hotel itself, there are lit candles, candelabras and torches throughout, most noticeably in Mavis' room during the scene where her monster friends (Frankie included) are addressing her idea of going to a human village. None of this fire affects Frankie at all.
Suggested correction: Candles are a controlled fire, and small in a room that's mostly made of stone. The match at the town was a sudden fire in front of his face that startled him. Even if he was concerned by the candles in the past, I'm sure that in the 115 years since the hotel opened, he was OK with it.
Plot hole: Drac was unable to hypnotize Johnny due to the contact lenses, but he somehow was able to hypnotize the airliner pilot through the thick window.
