Although the Luftwaffe did have a 'flying-wing' designed aircraft, this particular plane depicted in the movie did not exist. The closest real-word aircraft most likely would have been the Horten HO-Vc, and the Arado E-555 (which was a jet).
The flying wing here was chosen by director Steven Spielberg to represent the ominous and advanced state of aeronautics in Hitler's Germany. Production designer Norman Reynolds used a Northrop Corporation prototype of the Flying Wing and drawings by Ron Cobb to design for Raiders of the Lost Ark. The plane was built in England by Vickers Aircraft Company and painted at EMI Elstree Studios in London. In order to ship the elaborate prop to Tunisia for filming, it had to be disassembled and sent in parts, then rebuilt on location.
More info here:http://www.indygear.com/props/planes.shtmlhttp://www.airbornegrafix.com/HistoricAircraft/FlyingWings/Ho5c7.htmhttp://www.luft46.com/arado/are555s.html
But enough geeky aircraft-design talk, enjoy the fight!