are they already engaged when you go after them??
No...
my formula.
1: Don't fly with hordes.
2: Don't fly with missions.
Obvious... neither will get you anything to fight.
Going further...
1: Find a capped friendly base.
2: Fly out of the nearest friendly base to the capped base (not out of the capped base, of course).
3: Climb to 15-20k (yep) so that you can chase the cherry pickers down to the deck.
4: BnZ your way down to the deck.
5: Once your on the deck, run, hoping you have E. Run until you've made it decently far from the main horde and theres only one con on you.
6: Engage the single con

Sounds ghey, but consider the cons at your base were only vulching anyway. It's pretty fun and pretty much the only way I've found not to get gangbanged unless your flying with a wingie.