I haven't read through all 6 pages yet (or whatever...)
but the best tip I have I discovered by accident while flying with Sugar.
She was a bit out of sorts in her carrier and was hungry/thirsty. I couldn't unzip the bag or she would escape
so I took out the syringe I had for her benadryl if she needed it (she didn't
) and filled it from my bottle of water. I was able to squirt it slowly through the mesh in her carrier and she happily lapped it up
I now never leave home without one in her bag!