The plane is supposed to be landing at Seattle. However, the emergency vehicles have labels reading "Dallas Municipal Airport."
When the helicopter shoots holes in the elevators, close-up shots show the bullets passing through them in the wrong direction.
There is no way the AH-64 Apache helicopter would be able to keep up with the jet, it would also be severely limited due to the altitude, helicopters can not operate well at altitude.
Aircraft have oxygen holds only for flight crew, not for cabin and only for emergency. The masks you can see in the cabin are chemical oxygen generators, which generator oxygen only for half an hour. Normally oxygen is provided by the engines. They take air in through the engines or other intakes and compress it to give a pressurized cabin, not holding oxygen in a compartment.
When the cockpit hatch is opened, objects in the passenger cabin are immediately blown backwards. They should be blown forwards until the decompression via the hatch is complete.
If '48C had taken off from 9L as it was supposed to, it would be on almost the same course, only displaced to the left by the distance between the runways. If the actual position of '48C following takeoff from 9R created a collision course with Quest 19, then the intended position would still have created a dangerous close approach. Therefore no such order to turn would have been given.
The pilot asks the tower to call out the altitude because he doesn't trust his instruments, however all readings the tower can see come from his instruments relayed through a transponder to their secondary radar screen.
When Questair is taking off, you can clearly see the word 'Canadian' on the side of the plane.