Pick one category for the following text. The options are - company, educational institution, artist, athlete, office holder, mean of transportation, building, natural place, village, animal, plant, album, film or written work. Heinkel HD 55 - The Heinkel HD 55 was a biplane flying boat produced in Germany in the early 1930s for use as a reconnaissance aircraft aboard Soviet warships. The design was based on the HD 15 mail plane of 1927 and was a conventional design for its time with equal span unstaggered wings and an engine mounted tractor-wise on struts above the pilot's open cockpit.
Mean Of Transportation