If you set your entry and exit points then that in and out direction will be used, except as it sets up entry on the target initially selected near the impact point, then it may shift the entry to line up. In other words, the impact point selected has a large part to play - and that gets rolled for if there is no target aquision near there on entry, which can shift the impact as for other arty, and again, the netry sector may then shift so the inwards path can actually point at the selected target hex.
The exit direction can move from the selected, if the above happens. And if the strike plane strafes stuff off the axis of flight, it can decide to fly straight onwards after weapons use. And if it finds nothing and beats up some empty ground - it decides where it wants to leave by.
The air farce is
not part of the army, so you influence it but you do not command it.
Generally speaking, I dont bother with strike air - the points are better used on arty etc. If advancing or assaulting then air strikes are useful for spotting defenders though. WW2 air isnt a real tank killer. Modern stuff with long range missiles are a different kettle of fish!.
In an operational level game air
would be vital since your airbases can be used to fly off to widely spaced battles, hit his supply nodes, airfields etc. In an SP battle, your arty is always in range.
Air power is an operational and not a tactical tool, but the designers probably put them in because "rule of cool" and end user expectations, see the Mustangs in Saving Private Ryan forex, and the popular perceptions of "cab rank" air "slaughtering" tigers in Normandy.
In reality it was the total destruction of the German supply column trucks and horse wagons that were the air "killer" effect - and that is operational so not this game's focus. Blow up the beans, bullets and fuel and the clockwork mice eventually run down and the troops get peckish and the rifle becomes a spear body for the bayonet.
The A10 therefore wasted weight on a humongous internal cannon, because its true target really was supply columns which a 20mm vulcan can service just fine and weigh less, or have more ammo supply for the same dead weight as the somewhat iffy 30mm AP ammo performance post the T-55 and T-62s. Long range tank plinking with guided missiles did not neet a ton of armour anyway. Yep, me is in the A10 is a silly idea camp
! - Sturmovviks were moderately useful at the end of WW2, but not post war.