Revealing mistake: When Lisa stabs Jackson in the throat with the pen, if you watch closely, you can see that she is still holding the pen when she pulls her arm back, but in the entire rest of the scene the pen is still stuck in his throat. If you watch it in slow motion, the mistake becomes even more obvious. (00:56:15)
Revealing mistake: When Jack is falling down the stairs, you can see a pad on his back. (01:05:00)
Revealing mistake: When Lisa kicks Jack causing her shoe to stick into him and for him to go falling down the stairs, you can see the face of Jack's stunt double. (01:05:00)
Revealing mistake: After Lisa has escaped from the plane, she is spotted by Jack and is getting chased by him. When she runs through the travelator she trips over at the end and it is obvious that it is a stunt woman, and not Rachel McAdams. She looks nothing like her.
Answer: These are very tech-savvy terrorists. Not only would they be watching Keefe, but also Lisa, who is integral to their assassination plot. The assassins would have been monitoring their every move, intercepting cell phone calls, hacking into the hotel's and the airline's computers, and so on. It is unknown how Jackson got a seat right next to Lisa, but as it's a late-night flight, there would likely be fewer passengers and he could have managed to be seated next to her or somehow got the airline to switch him with another passenger.
raywest ★