Transporting Precious Cargo?

As I stated before, we are planning on relocating by the end of the year.
We have 3 dogs, my husband can take one when he drives over to Biloxi. I can take the younger one when I go.
We have an older boy he is an 11 yr old Rottweiler. He has arthritis in his back legs and lower. He is able to get up and walk around. He cannot get in and out of a vehicle.
I would like to arrange air transportation does anyone know of a good service?
Or suggestions for our boy?
Thanks 😘