how to survive air attacks on vulnerables.

[nodlew]

Which TOW game are you playing? I'm really only familiar with Korea. In that game, if you have fighter support available, you should immediately call for it when you hear the sound of enemy planes. Infantry should should lie down, they will survive strafing much better that way, also they should not be bunched too closely together. Mortars and field guns are high priority targets for the enemy planes. You can dismount the crews from their guns and have them fall prone as well (this is also a good idea with the crews of open topped tank destroyers, like the Jackson or the SU76, else the gunners and commanders will likely not survive an air attack or mortar attack). They will survive strafing much better. Bombs or rockets? Maybe.

Not sure how well trees and bushes hide your troops from planes--probably not very well since planes easily spot entrenched infantry and gun emplacements.

If the planning stage if you think the enemy might call in fighter bombers, get some AA if it is available, although I have found their survivability to be very low since the planes attack them ferociously once they are spotted. At least that means your other units are being spared some attack runs, and occasionally the AA guns shoot down enemy planes, which are worth a lot of points toward reinforcements, artillery support, etc.