The Horton 229 was a twin-turbojet, flying wing interceptor that first flew in 1944! It was the culmination of many years of flying wing design by the Horton brothers. The museum's example is the V3 or third prototype. The V3 was not quite completed by war's end, but the V2 did fly.
Horten brothers, Walter und Reimar, convinced pure flying wing would minimize parasitic drag and provide efficient low-drag airframe. Built their first flying wing, Ho I sailplane, 1931. Power added to some later versions culminating in Horten IX, first turbo-jet powered military aircraft with pure flying wing configuration. (During WWII, Jack Northrop's work on flying wings seen by Germans as potential threat, and validation of Horten's efforts to develop jet-powered Horten IX.) Before attempting powered flight, first prototype Horten IX, V1, with no engines, flown as glider to test aerodynamic characteristics.