This is an example of the trousers from the Luftwaffe two piece electrically heated "Kanal" suit. They became standard issue for pilots and aircrews sometime in 1943.
This flying suit was obtained for research by the U.S. Army Air Forces Foreign Technology Division (FTD) during World War II. These items were made available for study by commercial firms who could then incorporate any improvements American flight clothing.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.