The hijacked plane starts out as a Boeing 747. When they land to refuel and exchange passengers, it becomes a Lockheed TriStar. It changes back to a 747 in subsequent shots.
The lower level galley used by Murdock to gain access can only be found on either a DC-10 or Lockheed TriStar and not a Boeing 747.
In real life, the chances of survival would've been better in water than on land. The tower would not have to give a "false heading" to have them ditch the plane in the sea because that would be their best chance of survival.
Although the plane is supposed to be Beller Air, the words Trans World can be seen on the side and TWA on the tail.
When the cabin window is open, we can see a shadow of a C-stand holding the background of the sky.
The 5- million- dollar ransom would never fit into a standard briefcase.
When Smith and Face are shown in the cockpit it's clear there is no pane in the window.
When BA pulls Murdock up in to the hatch of the aircraft, he says 'Get up here fool!'. Yet his lips don't move.