I thought about this when driving back up north this past week (flights out east got cancelled) as I figured no pilot would do a suicide mission (at least not 3 in a day) and that the hijackers had to be at the helm and would concur with most that it was a do or die anyway situation.

When I heard it was knives that were used, I thought that grabbing a seat cushion flotation device or two, and then using these as shields, would be a good way to rush the hijackers. The straps can be wrapped around your forearm to hold the seat cushion in place.