t1 aa is close-in weapon system so it should act as a point defense for cruise missiles and aircraft. t2 aa should be a longer ranged missile defense and anti aircraft system t2 bombers should fly over target at high altitude and the only real threat should be t2 interceptors t2 interceptors should also be flying outside of t1 aa's range. when t2 interceptors swoop in to kill t1 intercepters over aa; they will drop altitude and be fired upon. t1 air scout should also be a high altitude plane
Having T2 aircraft be immune to T1 AA would make the T1 AA worthless against players who never use T1 aircraft and would be very reminiscent to what the orbital layer currently is. As with most of this games T1 to T2 relationships, T2 stuff should be more specialised versions of the basic stuff, but with more obvious weaknesses then their T1 counterparts who don't suffer as much but are less effective. T1 fighters and bombers would more likely be the ones who are hard to hit (Thus the missile AA) leaving the slower but tougher T2 planes able to inflict more damage and can receive more but are bad ad dodging are would be more susceptible to slower AA systems.