Hekk ya you need an airstone!
I use an airstone w/ any fish in travel...whether its 2" or 16".
With large bass i would get a large 29-37g rubbermaid tub....bigger if you can fit it. I would get an ac adapter you can plug into your lighter. IMO battery opperated pumps are too weak. Plug in a large air pump and airstones. If you have an extra canister filter i would use it as well. Seriously! Big bass need tons of o2. Keep your car cool while in transit to your house. The more oxygen and water movement(filter). The better.
Seriuosly! Therr was just a thread on Here about how sensitive orinos are. Be very very careful! Especially with such a good deal you have money to spend on proper transport!