A rare situaton IMO.
In the MA, it's always;
a) follow your own horde and go play at a vulched enemy base/airspace
or
b) oppose the enemy horde hitting your totally abandoned field, up all alone, and throw a finger at your teammates who's "strategy" is to abandon all bases in face of enemy threat, and go join up to hit an enemy base/airspace which is already subdued for a long long time, and then come back and 'reclaim' the base when all the enemies are bored and have gone home
...
Coming back to the original question...
If an enemy horde actually forms and pushes back your horde, the chances are, your own horde will just run away and go hit another undefended field, instead of staying the conga line and having some A2A fun.
Therefore, a) and b) and c) is actually the same in end result. If you stay in that airspace you'll have a spectacular experience of witnessing how all your friendlies can just vanish so quickly, "gone with the wind", in the face of determined enemy challenge.
So, whatever the choice you make, it doesn't matter. If you're a person who hates flying with hordes, then you're gonna buy it anyway.
