Deleted my first post since I thought you were talking about both GS and Airplane.
But here is my response:On getting shut down:
Getting shutdown due to air means that the AA on the enemy side has increased to such a point that planes can no longer fly through without being shot down.
This seems to be the case with Chainsaw and Artemis, which easily blasts most planes out of the sky.
However: Once AA has progressed to that point, there are generally 2 options - Their army is weaker due to them spending more on AA, or if not, then you are seriously losing.
In the second scenario, consider resigning. In the first, your options are to either strike their army with a ground force due to being weakened, or hit them with a special weapon.
Once the enemy force has been engaged, they will suffer from attrition, and this is likely to be their mobile AA as well, which means your aircraft should be able to Thunderbird/Wyvern the remainder of their army to death. Same thing with Static AA: Go for the Static AA if your army is weaker first, as it allows air support, then do the same thing as previous: Thunderbird/Wyvern the remainders to death.
Another option is to make decoy AA such as Swifts, flying them over AA whilst in boost means they will waste the AA's shots, and allow your actual strike planes to come in and deal damage. This is particularly effective against mobile AA since they have reloads and cannot deal with being baited easily. If the army has so much AA this does not work, then go for the ground assault as shown in previous paragraph.
Finally, you can simply THROW MORE PLANES AT THE ENEMY
The most brutish of options, you go for their army with strike planes (preferably Wyvern) and proceed to bomb them without caring about your losses. Or their AA. Just make sure you turn the tide since planes shotdown using this method WILL be easy to reclaim by your opponent.
Essentially, you must find a way to allow your high burst damage to get to valuable targets without being shutdown. These 3 options are simple ways to do so. But if your air is strong enough, once AA cover goes down, your opponent's army should be absolutely savaged by your airstrikes, which allows you to forgo an army that is capable of going toe to toe with your opponent. All three options still work even in lategame, you just need more units to do so. If you fac switched since you hold an economic advantage, this should be relatively easy to accomplishOpinion
Planes, I think, should be easy to shutdown in the form of AA. This is because they have extremely high amounts of burst power that can easily turn battles in your favor. If planes were made stronger so that it takes more AA to take them down, then planes will have an easier time savaging armies on the ground, and means that the third option, yeet more planes at them, will be more viable, which I think is unhealthy for an RTS game, since it makes the player with an economic advantage even stronger if he fac switches to air, which might just make him unbeatable due to air's extremely fast reaction time.
Here's another thing to consider: If the planes survive and kill a target, they have managed to cost your opponent metal without costing you any metal. This means that planes gain an exponential effect, as each time the planes succeed, the weaker your opponent gets whilst you remain the same strength. This will lead to lopsided battles where the planes win simply by being strong enough to attrit your opponents down while not being whittled down themselves, as they cannot be traded against once they are at strength.