Villian mistakes. The keys to being a succesful criminal.
As a modern day terrorist, or kid napper, in order to win you have to beat the system that's in place. Coffins that doesn't get x-rayed, hide bomb detonator and c4 on it.. Smart. Choose someone who knows the plane inside out. Smart. Pose as a federal agent, Smart. Keep 2 guns on you, smart. Have someone on the inside to help take her daughter off the list or not put her on the list in the place, smart.
For someone who makes so much planning, and effort to execute this plan, he made some stupid mistakes.
1. Going back on the plane, that was his first mistake. He should have put the detonator on her sooner and shot her.
2. Taking his eyes of her, while closing the airplane door. You should never underestimate anyone, that is one of the key rules to being a successful criminal.. you don't give people a chance. Just because good guys give criminals a chance, doesn't mean us bad guys have to do that.
3. Drugging her child with a sedative. If your going to blow her up, why not just inject her with the some lethal poison instead.