Shown above are four maximum cards with the 25-cent Classic Mail Transportation commemorative stamps issued November 19, 1989. The text from the back of the cards is shown below the corresponding image.
The stamps are from a block of four stamps that was during WORLD STAMP EXPO '89 an international philatelic exhibition sponsored by the US Postal Service. The exhibition took place November 17-20 and November 24-December 3 in conjunction with the 20th Congress of the Universal Postal Union. The stamps feature vehicles that have delivered mail and range from colonial America to the early twentieth century: the stagecoach of 1850s, paddlewheel steamer, biplane, and depot-hack type automobile. (source: 20th UPU Congress Issue)
This is a post for Sunday Stamps at Viridian's Postcard Blog