Towbarless tugs are great. I just flew out of A-2 (satellite terminal) at DFW
, and the ERJ I was on had a much, much smaller tug than in the picture above. It looked more like a lawnmower. The operator stood on a small platform at one end of the tug and steered with a large wheel. There was no enclosure. It was almost comical to see these tiny tugs pulling ERJs around the ramp area, some of them empty and traveling at a higher speed than would normally be used for taxiing!
The last time I was through that area (about two months ago) they were still pushing back ERJs with towbars.
On another DFW
note, I saw the SkyTrain running around the main airport building complex, and was excited to think I might finally get to ride it! Sadly, it was not yet in service, and must have been running just for testing. The 1970's Robo-TrAAin is still in service, for now.