MrQ is disabled enough to be eligible for handicapped parking placards for his car.
We have never had a problem getting an electric cart at DFW. We either flag one down after getting off the plane or we ask a gate agent to call one.
We have been through ORD exactly one time since he became disabled. I asked for an electric cart, but was told they did not have them. It was either get pushed in a wheelchair or just walk under his own power. MrQ did not want to get pushed, so he walked the distance, slowly, but we made it.
Since then, I've avoided ORD connections when traveling with MrQ.
I may be very mistaken, or things could have changed since we were there, but I don't think ORD AA concourses have electric carts.
Please, someone, correct me if I am wrong because I would like to know for a fact one way or the other.