I think its ok, the idea is that they don't hit the magic invisible wall that's just past the point which teleports you to deep sea, which in turns allow them to go through it, then that gets detected and triggers a kill on them.
You will hopefully not see any more of them stuck as they spawn and fly off naturally over the coming day
Here's a generated representation of what the deep sea portal is actually like, since the CH47 wasnt triggering entering the portal , it was just hitting the backing collider and gettin stuck there
In vanilla, that wouldnt be a problem, but in the plugin we drastically increase the height of the portal, to allow flying vehicles to get in (rather than getting killed for being outside map bounds)