Plot hole: When Rane and the other terrorists come out the bottom of the plane and start walking towards the fairgrounds, it is amazing how not one police officer or staff member of the airport notices that they came out from under the plane, or that they don't seem to be walking off the plane like the other passengers.
Plot hole: When the police and FBI arrest Rane at the fairgrounds, Cutter tells them Vincent (one of Rane's men) is also at the fair, and wearing a tan jacket. Cutter did not see Vincent leave the plane and never saw him at the fair, and when he last saw him on the plane he was not wearing this jacket. So how could he know Vincent was at the fair and wearing a tan jacket?
Plot hole: The airport at which the plane lands is only supposed to have a small airfield. Yet near the end we see the huge plane roaring down the runway for more than a minute, which would be impossible on a small airfield.
Plot hole: Liz Hurley, who is one of the hijackers, learns that Cutter is an undercover security agent. Yet for some reason she fails to pass this on to any of the other hijackers. When they take over none of them appear to have any knowledge of Cutter.
Plot hole: While Cutter is in the bathroom, the first thing he hears of the terrorists taking over the plane, is one of them yelling "sit down". If he heard that, how could he have not heard the gun shots when Ms. Ritchie shot the FBI agents, or the sounds of screaming passengers?
Answer: I just rewatched it this morning. When Rane is trying to persuade Sheriff Biggs that he means business, one body (presumably The Captain) is thrown out of the plane. Just before the passengers are released, we see a quick shot of yo ambulances. One has 3 full occupied body bags in it. Therefore, it's implied the other two are in the other ambulance. This takes place before the FBI guy gets there. The fact that he tells Rane, those guys you killed were my friends" means that at some point they were identified by name. He could've found out numerous ways (Washington told him, briefing, the paramedics, Biggs, etc).