If you mean "Aerials" and not "trows" (that's in judo, not swing) then weight has nothing to do with it. Timing and technique are important (if you are doing any aerial worth doing). Granted a lighter girl is easier, but again, it shouldn't matter. And be sure you are learning aerials that you do in Lindy Hop, where connection and technique are important so no one gets hurt.
I'm on a competitive lindy hop swing troupe, and we have a girl who is 6 ft tall and about 180 lbs, and she can do several aerials with a guy that weight about 120, and is 5 feet tall, so again weight doesn't matter.
Also, we know a couple of "aerial squads" as we call them that don't do any true dancing, just aerials. Don't fall into this group of people as you are missing out on the best part of swing (the non-aerial part), and most of these groups don't have formal training on how to do aerials, and people are hurt all the time.