If people think the plane is about to be flown into a skyscraper, I'm not sure a gun will stop them. There are hundreds of people on a plane and at most twenty rounds in a gun. The math isn't in the terrorist's favor.
There also isn't room to get away from angry passengers. They're probably going to overwhelm terrorists with guns relatively quickly.
I don’t believe I’m making up this scenario. But here I go..
I would book a first class flight in the first seat in front of the plane. Make all of the first class passenger - fewer of them, probably wealthier business travelers who don’t think they are Rambo - move to the back of the cabin.
The aisle would be the perfect kill zone. I watched a documentary and they said SWAT training for taking over a plane from terrorist they know that whoever goes in first is likely to get shot.
There also isn't room to get away from angry passengers. They're probably going to overwhelm terrorists with guns relatively quickly.