Aircraft can currently target:
Infra
Troops
Tanks
Aircraft
Ships
Money
Of these, infra, troops, tanks, aircraft, and ships definitely make sense from a realism perspective. Money I'm not sure about, but there must be some reason why we're allowed to drop a bomb on a large pile of cash.
Things we're not allowed to currently bomb:
Missiles
Nuclear weapons
Spies
I 100% get why we can't bomb spies, I mean seriously... how would you do that? It would be like trying to bomb ISIS... Being able to bomb nukes would be nice, even if you were only able to knock out 1 a day or had say only a 25% chance of hitting, but I understand that many nuclear capable players don't like the idea of their very expensive stockpiles (presumably buried far under ground) at any more risk than they already are. Bombing missiles, why can't we do this? Surely in a real war ICBM launch sites are determined quickly and open to strikes? Using a similar mechanic to ships in a harbour, tanks in a depo, aircraft in a hanger, or soldiers in a barracks?
tl;dr please let us bomb enemy missiles