When a gasbag has any amount of air in it has an 80% damage reduction (same as reaper king). Because of its great reduction, ability to wear saddles, have imprint bonus, eat veggie cakes, and a mate boost, it’s arguably the best tanking dino, but whenever it’s hit it looses a small amount of gas.
If you run out of gas and are falling to your death, right before you hit the ground, dismount, and your fly bean will be safe, and you will land on top of it. Works every time if you do it right. Also this literally works for every other creature.
Gasbags is one of the best support tames in the game. It has great weight, is tanky, and when you level up speed, it can go very fast while flying. Not to mention but they are adorable. I suggest players get gasbags on both PVP and PVE. The only drawback is it does no damage and if you aren't careful you can kill it by falling to your death.