Yeah. So can dynamite.
So can a boxcutter...
Not any more. Not if any of the passengers has gonads. And you can bet they all will, knowing they're dead otherwise.
This is the dumbest thing about the TSA. Bin Laden will never be able to take over a passenger airliner again with box cutter. Even if he smuggled on guns there probably wouldn't be a possibility now that people know the result of a hijacking could be their death (instead of a flight to Cuba).