[travelstiles]

All very good suggestions.
We drove this past December from NY with 2 cats in a Mini Cooper. We had gotten sedatives from the vet prior to our trip, but never needed to use them. Thought for a while hubby would need them, not the cats ;D
The cats complained for about 15 minutes, then slept.
We used our 2 large cat carriers with wee wee pads in the bottom and stopped every few hours to place food and water in the carriers.
We stayed at Comfort Inns along the way (2 nights over 1100 miles), and when we left the room put the Do Not Disturb sign on the door so no one would enter.
Both cats did amazingly well, and the older one is about 12.
As far as Mom, I had taken my parents on trips when they were in their 80s, but they really couldn't take more than 5 hrs a day riding in the car, with several stops along the way. You could do this if you have the time to make it a relaxing ride, as Red suggested.
I personally would find a plane trip more aggravating than a few extra nights on the road, especially with how the airlines are now, and particularly for an older person. The cost of the flight is probably more than a room at a motel and a nice dinner.
Good luck and enjoy your trip!