[EASyEightyEight]

I rather like how AA works in PS1 right now. Missiles for everything close, flak for everything up to the flight ceiling. Most people can't seem to hit anything that high anyway (I'll never understand how some people can't seem to lead a target.) I don't see any need to implement flak that hits harder the higher the altitude, that just seems kind of forced and doesn't feel too balancing towards aircraft. If something is that high, it's likely not doing too much damage. Bring in more flak cannons or throw aircraft at it to handle it, not beef one cannon up.

For lower flying vehicles, it would make sense for the alternate fire to use lock on missiles, ala the Striker (fire-and-forget is freaking cheap, and I say this hating aircraft with a passion.) Though, this is the part where a pilot could opt to upgrade their bird with counter-measures at the expense of something else useful (like afterburners?) On this note, I do agree with flak requiring a minimum travel distance before exploding into a cloud. It's shrapnel, not a puff of smoke. Detonating at 5m off the ground or from the barrel of the gun would do more harm than good. In this way, if a bird gets in too close, a single AA may be hosed, but a bird that close just means it's in range of literally everything else.