highly recommend going as far away until you can't hear any sound effects coming from them cuz the range where you can't hear their flying or attacking sounds is a good estimate if not exact to their aggro range

more tips:

idk if this is with all flyers but they really hate it when you fly cuz theres a high chance they will stop attacking the creature theyre attacking and focus on you when you come near them and only focus on you (i tried this with another rhynio) so try to land next to another paracer nd hope they target the paracer instead

and lastly if youre being shot at try slightly running in circles cuz you will get hit last