An emailer says:

I can't understand why you take such a negative point of view on the solution of aerial acrobatics to disarm terrorists, which I had missed in the news. Please give it a little more thought, considering it in a little more detail.

It will simply require a plan to be developed in stages, as follows:

1. Teach airline pilots to roll successfully, in the aircraft in which they are qualified.
   
2. Teach advanced course of four-point slow roll.
   
3. Revise A/C safety lights to announce, "Fasten Seat Belts, NON-TERRORISTS ONLY"
   
4. In event of attack, perform Maneuver 1 and announce "Anyone standing on the ceiling, put up your hands to promise you will surrender...If you refuse to do so we will get quite upset".... then perform maneuver 2, until the flight attendants catch each perpetrator and cuff with plastic cuffs.
   
5. Before issuing this directive, check with the Administration to get approval for plastic cuffs, but in no event shall these be issued for flight crews, whose judgment on such matters is highly suspect.

Oh man, he left out the most important part of all:

All flights must file reports immediately on landing, breaking down statistical demographics of persons restrained by the flight crew. Any disproportionate representation by ethnicity, religion, national origin, gender, sexual orientation, or disability status will be considered prima facie evidence of profiling and each such offense shall be subject to heavy fines and other disciplinary action as determined by the Congress and/or Secretary of Transportation.

I think you're missing the boat on this one. Most airline pilots are ex-navy or ex-airforce so teaching them to roll, etc, would not be that big a deal.
Also, the terrorists will be standing and attempting to knock in the cock-pit door, or keeping the passengers intimidated prior to the manuever so they will not
have their seatbelts buckled. Anyone unbuckled takes the risk.

I quick decent in altitude would probably launch said terrorists into the roof of the cabin, hopefully giving someone the chance to deal with them. Its been known to happen
that people break their necsk when a plane drops suddenly and they hit the roof. That might be a bonus to the maneuver.