@Aktungbby: Before 1940, but i am sure it has been in service by the Luftwaffe in 1940, if not as a bomber or in a typically military role as far as i know.
@Jim, and Aktungbby: Not a Junkers G38
(and the photo of the Junkers is nice though the Mercedes seems to have been photoshopped into it
. The G 38 is worth an own thread, it was gigantic for the time and almost futuristic, if there would not have been this old-fashioned tail. Junkers had planned to build a giant flying wing, and this was an experiment in this direction, with some passengers sitting in the wings and havin a a nice view ahead..)