Factual error: One of the subplots involves a young boy ("Tommy") who is bitten by a cobra and the attempts to save his life. When they are working on his arm, it is horribly swollen & filled with fluid which they drain by cutting open his arm. Cobras secrete a neurotoxic venom which attacks the nervous system. It would not cause noticeable swelling at the bite site. The symptoms Tommy has would indicate a bite from a snake which secretes a hemotoxic venom (such as a rattlesnake), which attacks the blood stream & tissues, causing swelling.
Factual error: The altimeter is obviously fake. On a real altimeter there is no second hand and there are no numbers that indicate tenths of a foot. On top of that, the altimeter in the movie reads 3,000 feet when they hit 35,000.
Factual error: The plane being used is a Boeing 747. The first class cabin is upstairs, yet shown to have two aisles. The upstairs cabin in a 747 has only one aisle.
Factual error: When the second toilet victim enters the plane's toilet, the overhead light is already on. In a normal airplane situation, the light only comes on once the door is locked.
Factual error: When the couple go into the restroom to have sex, they dis-engage the smoke detector, yet nothing happens. The pilot and the stewards would have been notified by alarm that the detector had been tampered with.
Factual error: When the flight crew declare a mayday, they talk to LAX tower. However, the tower's radios wouldn't have the range to receive these transmissions as the tower only controls the airspace directly around the airport. Likewise they would actually be talking to Oakland Oceanic Control (not Oakland Area Control Centre), as the sea area between the Western Seaboard and the Hawaiian islands falls under Oakland's FIR (flight information region), and thus the flight is their responsibility.
Factual error: When they track the down the snake keeper that had the snakes he was bitten. The snake expert went into the fridge for the anti-venom and it was already mixed in the vial. He then loaded a syringe with the antivenin. This is a major flaw. Antivenoms have to be mixed. They are never in a vial ready to go. They are always mixed and warmed in a solution prior to administration.
Factual error: When Neville Flynn is going to reset the breaker for the A/C he is in the cargo hold. He moves aside a shipping container, a unit load device (ULD). This unit load device had a big sticker across the top of the side. All ULDs are required by FAA regulations to have the identifying number on all four sides at the highest, most visible point. There was no identifying number on the front and there was none on the side. Where one belonged there was a big Pacific Air sticker. This was more than likely covering up the ULD number that was borrowed from another airlines.
Answer: It depends on whose airspace you are in when it occurs, whether or not anyone else sees you (public indecency), the laws of the nation that the airline is based in, etc.
Grumpy Scot