I don't agree with the premise that 32" of movement by a ground unit is equivalent to 32" of movement by an aerospace unit. Speed in of itself isn't the issue that makes you hard to hit. The calculations necessary to properly lead a target at a given speed and range have been perfected over 1000 years ago as of the time most Alpha Strike games are set. What makes "fast movers" on the ground hard to hit is their ability to juke and bob and weave. Suddenly stop. Suddenly start. Hairpin turn. Sidestep. Etc. The aerospace units rocketing overhead are moving very very fast, but also very very predictably. They can't "juke" the way ground units can. Just lead the target, and the Aero unit can't help but fly right into the shot you send up into the sky.
That's just it, 32" of movement is the MINIMUM movement needed to stay aloft for modern aircraft. Ground attacks are typically done at much higher speeds - 150 to 200 MPH, or about 46+ inches. And while I agree that movement alone isn't the only factor on targeting, the AS rules don't support any "juking" unless you use Evade. Besides that, advanced aircraft would have countermeasures, flairs, radar jamming equipment, chaff, etc. And the lack of cover is a big deal.
I keep coming back that aircraft need to have declared elevations. So if I want to be at medium range, I come in at an elevation of 12" or whatever. It's easy to do. Just place a d20 as your elevation marker.
And I don't really agree with the basic modifiers to hit for things like striking with a +4... Just let me use my TMM, Cover, and skill like normal. That makes aero much more effective (perhaps too effective), but that should be reflected in the PV.
I'd be happy with a default 4 TMM for Aero, losing the "airborne" mod for taking a straight path. Then add range mods like normal. So if you want to come in at 6" elevation, ground units need 8 to hit you from short range.
Lastly, range should be measured from the flightpath to the ground unit or elevation, whichever is higher. I know that's not precise, but its "close enough" for tabletop gaming. So if I'm 6" from your flight path and you're 6" elevation, I'm shooting you from 6" (actual Pythagorean distance would be 8.48").
Anyway, these are ideas I'm putting into my house rules doc. I'll have to come up with an easy modifier for the aerospace PV I think.