I don't even sweat it anymore.
It's the mission that counts.
If it means approaching B17s dead six because they are about to drop on strats, I will take that opportunity rather than wait until after they drop.
If an enemy escort is on my six at the time, I will deal with him after I've taken a shot at my primary objective.
Same goes for deacking or strafing troops or killing the goon/m3.