Yes, their losses were very high, from gliders being shot up and crashing, to men dropping into trees and rooftops where Germans machine gunned them.
Hard to imagine the amount of courage it took to jump into that hell.
If you watch the first 15 minutes of “Band of Brothers” episode 2, that is as gut-wrenching as “Private Ryan.” A lot of paratroopers on those planes never got a chance to jump.