Originally Posted by choster
"Moon buggies" they're often called. Here are a couple of links:
http://www.airchive.com/SITE%20PAGES/PLANE-DULLES.html
They are building a tram system to connect the midfield terminals, so the mobile lounges may be retired soon. They are not much loved, being slow and often crowded.
The post above shows a picture of Air Zimbabwe parked at Dulles.
I don't recall Air Zimbabwe flying to Dulles.
It is most likely an Ethiopian Airlines. The only African carrier flying now to IAD.