I once had two pteradons and was going to rebuild my base in other place, what i did was i made one ptera to folow another and was flying to place i wanted (all my stuff i needed was in my pteras' inventory) and then i tought about starting flying on the folowing ptera, and made first one folow that other one WITHOUT TELLING TO STOP following in previous way- the second i landed on ground and jumped of my ptera both flew right to the sun with all stuff and i never saw tgem again...

But they had an egg and it hatched, hope not do the same mistake again