Using mission editor (or manual editing) You can add more time to the delayed flights so that you get realistic number of squads performing missions at any one time. Or change them to standby flights so that they take-off when enemy planes approach. Either way there shouldn't be more than 10 or so squads in the air within a 2 hour block of time (1916/1917) within each region, I would assume. Give or take depending on if there is an imminent battle or quiet time. Or if there are any historians, they can correct my number of squads in the air every 2 hours or so.