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. (00:35:00)
Plot hole: Banning knows where there is an MI6 safe house but has "no option" but to head for the US Embassy. He could have gone for the Tower of London, Buckingham Palace, Knightsbridge Barracks, Downing Street, the Palace of Westminster or Scotland yard, all knee deep in security.
Suggested correction: The whole premise of not being able to go to the embassy is because they (the terrorists) will expect it. Banning also makes it clear to Asher that the entire security services are no longer to be trusted due to an insider. Going to any place "knee deep in security" is literally walking into a potential terrorist. The head of the UK response team even states they don't know who can be trusted and they need to eliminate the ones that have infiltrated the police forces. Hence the MI6 safe house.
Suggested correction: Considering the fact that there was a mole inside Scotland Yard, going there wasn't really an option.
Plot hole: They find the terrorists by the electricity they're using, but they're using generators, off the grid.
