Well its not so critical , if you manualy (HQ off) move a unit , it will start immediately , and 10-20 min before T/O … they should’ve moved already…
But…, yes, if there are more units “stacked” then it is a bit of a problem… you must wait till top unit moves untill you can give orders to unit “below” … in that case use MC editor and (cheat, cough… ) move those units to a nearby objectives,… after that … whatever you want, eg., resume those units to HQ .
AAA/AD units shouldn’t represent problem as they have pre-planned positions (points) on the airbase/objective , already preset around runway so they don’t interfere… if that’s done right for the objective/airbase .
Cheers