Description
image from page 12 of Wing Tips, Vol. 3, Issue 12, Jan. 1970. Caption reads: "One of tractors for new Jet Age: Pan Am will use three tractors to maneurver the 747 at different airports. The largest weighs 155,000 pounds; the smallest, the Hough, shown here, weighs 108,000 pounds. the tractors are only part of the costly equipment that the changeover to the new age of commercial flying requires."