Right after being killed by said C*S.
That’s because, when it comes to SPAA, you only have two options;
1: Spawn SPAA from the start of the match, sacrificing your fun by not playing for most of the match and being unable to play the vehicles you actually wanted to play; ground vehicles to engage in combat against other vehicles.
2: Spawn SPAA once C*S has already killed you, in which case it only serves to get a revenge kill in the best case scenario, or to get bombed from the stratosphere while your spawnprotection is still on.
In either case, “just spawning SPAA” is just not a solution.
Should there be a ground only mode? Maybe not.
But we certainly need to:
1- Increase SPAA rewards, in order to make spawning and playing them actually worth the time and effort.
2- Implement significantly more capable SAM systems; at least Pantsir S1-equivalents for EVERY nation, including Type 81 (C)'s Active Radar Homing missiles (they are in the files, why are they not ingame yet?), HVSD/ADAMS or SPYDER for Israel, and even Patriot-like systems (at least the devs already stated to be working on these, but we simply need them ASAP ingame).
3- Implement an SPAA extraction point in the spawn zones (tested in 2024’s April Fools).
That way, players can spawn SPAAs and, if they aren’t being needed, they could extract them to spawn back in a tank, so that they can spawn the SPAA later, whenever needed, instead of having to waste the entire match on a potentially unneeded SPAA. This is, in fact, why many people are reluctant to spawn SPAA on the first place; SPAA extraction points on the spawns would solve this issue, again, further encouraging spawning them.