Sounds like a couple of airline mechanics talking!
*cough* I'm an avionics systems engineer, buddy; not a stinkin' wrench jockey

As far as ammo goes, my point is that the risk of airplane damage is not a huge serious risk unless we're talking about maybe rifle calibers. So frang ammo isn't going to negate the bigger risk which is collateral human damage. I say let the ammo the CCWer carries be left up to them except for incendiary ammo (yes, I have seen incendiary ammo in pistol calibers before). What needs to be thought about is how can we mitigate the risk of shooting OTHER passengers when there's a legitimate threat to life and limb by an attacker and one must shoot or die.
Here's something else. That plane is NOT public property. It belongs to a private corporation and is therefore private property. If that airline wishes to forbid firearms from being carried, then let them forbid them. Their property, their rules. If one then carries anyway and is made, then charge them with illegal trespass. Basic property rights right there. Of course I'd advocate an airline NOT forbidding the carry of firearms by certified (CCW-holding) persons, but I think first we need to get straight exactly WHO has the right to set rules.
I did just think of an idea. IIRC, the Israeli military has their troops carry their pistols in condition zero (hammer down, empty chamber, safety on), yet they're still pretty wicked fast on drawing and shooting. So,
with practice, it's a valid carry condition for CCWers (isn't my preferred method, but I'll admit that it's valid if circumstances warrant it). So, why not just simply require that any CCW-holder who is carrying on the plane carry with an empty chamber? That'll prevent NDs if the gun is accidentally dropped, or if someone is wearing a worn-out leather holster and the leather get jammed into the trigger guard. I'd say those conditions would be the most serious risk to other passengers.
Maybe a FAA-issued CCW (I cringe while typing this, because that'd just give MORE power to the federal government than it ought to have, but I can't brainstorm a better idea right now) where a valid CCW holder shoots a course of fire designed with ALOT of no-shoots, reasonable but stressful time requirement, and draw from deep concealment in condition zero to PROVE that one is capable of mitigating his own risk to surrounding passengers. It'd be good for a few years before having to go and requalify. Must already have a valid CCW (either residential or non-residential). It'd only be a qualifier to prove competency inside a cramped environment.