the planes don't turn into conveys as long as airfield exists.

it is not nonsense if you think about it. When you are fighting for province, as long as you do not capture it, it is under enemy's control.
Aircrafts fly off and damage your units then fly back and it repeats, difference being that you are more easily able to damage airstrip and aircraft itself.

should atleast greatly reduce its damage then, when the enemy is at the gates, fair enough you're realistically going to be scrambling airforces in the province less then a mile to assist in the fight as sorties, but you're doing just that, scrambling whatever is refueled and rearmed into the air as soon as its finished without waiting for the rest out of desperation, because with the enemy that close you dont have time to wait for a full powerd strike, so if the realistic reason for the mechanic where grounded planes still do considerable damage in the ongoing fighting within that region to exist is scambled sorties to assist the fighting, their damage output should reflect the fact they are indeed desperate scrambled sorties of throwing whatever is ready to go back into the air without waiting for the rest of the sqaudron let alone entire airwing to be refueled and rearmed too

Nonsense. That would be assuming the provinces are the size of my closet.
And unless the ground forces are actually at the airport, there is no "scrambling"

And with costs to planes, I am ok with them having a fighting chance

iam not okay with them having a fighting chance to be frank, simply because planes are disgustingly overpowerd as it stands currently, this coming from somebody that uses planes as a key part of my strategy so id know, so i honestly think realism be damned being caught on the ground should just straight up be GG