Plot hole: After an assault on the scale that's been witnessed, covering a wide area of London by extremely well prepared attackers, there's no way Marine 1 would fly to the airport at low altitude within easy range of missiles, and then when attacked, double back over the areas that have already been attacked where hostiles would still be present.Jon Sandys
Factual error: When they spot the guy with the missile from the helicopter, the pilot says "we're being pinged", and Banning says "stingers." Stinger missiles are infra-red seeking, passively tracking the heat of a target, so there's no way to know if you're being tracked by one or not. As a highly-trained secret service agent, he'd know that.Jon Sandys
Other mistake: The agent infiltrates Barkawi's daughter's wedding and sends a message to the US military to bomb the place remotely. On the agent's phone he types "Barkawi on sight" and clicks send, but there is no phone number or contact.
Factual error: When the President is getting out of his car, we see the thin doors, like any usual car. However, in reality, Cadillac One has thick doors that weigh as much a Boeing 757 door. Not to mention the vulnerability of the car used in the movie. There's a reason why the Cadillac One is nicknamed "the beast."
Continuity mistake: When Banning fights three terrorists when the lights come back on, the 3rd gunman's gun changes from a rifle to a sub. (01:16:35)