Which is your flavor? Mine is generally the second. I need the wheelchairs for anything like lines or standing around, because that hurts more than almost anything, and I need the electric vehicles for gate-to-gate. I first used them in Seattle, in 2001 -- and note that you sometimes need to be on top of it. Going to Vancouver (we rented a car in Seattle and drove north) it was fine at SJC, but when we got to the Seattle airport, they called the electric vehicle and told me to wait, and quite a bit later, they called to find out where the person was, and the vehicle had gone to the wrong place, where I wasn't, assumed I'd left on my own, and vanished. So you need to pay attention to time and make sure you're not forgotten.