I don't know what weapons are carried by air marshalls. A hole in an aircraft's fuselage can be disastrous due to the pressure differential ... a small hole can expand rapidly.
I anticipate seeing a LOT more air marshalls in the future.
I salute the passengers who overpowered the hijackers on one of the flights. Although the plane ultimately crashed, there was a great deal of valuable information obtained from it due to it crashing in a field.