These bizarre vehicles were once used instead of jet bridges to drive passengers directly on to their planes! Now, they are used to ferry passengers between the main terminal and the two satellite concourses at the airport
Definitely old school. But, yes very cool for avgeeks (like me) who enjoy all those live plane spotting channels like Big Jet TV. I first saw these giant vehicles on the movie, Airport 1975, which was filmed in part at Dulles, of course.
in Barcelona Airport They use a vehicle similar to this to lift wheelchair people up to the plane on the front right door, they have also a mini wheelchairs to take the people to their row and seat on the plane