In recent travels, I've noticed they are at the terminal in Orlando (MCO), Tampa (TPA), Pittsburgh (PIT), Akron (CAK), Jackson (JAN)
The thing I hate the buses is the chance of an accident. 2 Weeks ago, a bus had to slam on the brakes and everybody went flying. My wife ended up with a huge bruise on her arm. I usually try to get a side seat next to the rack so I won't go flying. I will never sit in the middle back.