The light aircraft which crash is shown before take off with square windows and the registration C-GBBP, and then in flight it has round windows and the registration C-GUTY.
Sam says to say the name of God in Latin to anger the demon, which he says is "Cristo". "Cristo" is not Latin, it is Portuguese and it means "Christ". God in Latin is "Deus", however, Sam said to say the name of God.
Sam tells Dean to go to the car and get "whatever will go through security." Once they're on the plane, we find out that one of the things Dean brought was "holy water." The bottle in which he's carrying it is far above the acceptable TSA limit; that water would never have gotten through security.
While the Winchester brothers hail from Lawrence Ks, which is in Douglas county, the plates on their car are registered in Sedgwick county, nearly three hours away.
When the stewardess talks to the pilot at the beginning, her lip movements don't match the words that come out of her mouth.