The camera is not taken into account in the spawn radius but the aircraft.
I had terrible experiences playing with attack jeets on ALiVE precisely because of the spawn radius in airplanes. If you increase too much, spawn / despawn will actually cause fps dropl (not because of ALiVE but because of the amount of objects appearing and disappearing, especially in areas with many enemies). If you reduce the radius, you have to be very close to the target for appear and then you run the risk of dying if it is an AA, MANPADS etc. I did a test with friends on a server and flying with more than 1 plane is really impossible because the fps of everybody falls absurdly!
My only way was to set the spawn radius at 200 (so the bots that are at an airport for example are visible) and use a drone to move to the attack area to spawn the targets. The problem is that sometimes the AR-2 Darter gets drunk (ArmaBUG) and takes too long to get to the destination or worse, is killed before arriving.
SpyderBlack gave some tips on how to replace this drone with an object that will call ALiVE_spawnSources and generate the spawn in a specific location but I could not get it to work.
One possibility could also be: Once the ALiVE generates an air-related task like CAS, SEAD for example, it creates an object using spawnSources and deletes it as soon as the object is destroyed. I do not know if it would be possible but it is a suggestion to the devs.
So players on planes can view and attack their targets at a safe distance without knocking down their own fps or everyone present. As I said, more than 1 plane on the server can create many problems when the spawn radius is high.