There is an excellent book on the topic, titled Man Made UFOs, 50 year of Suppression, 1944-1994, by Renato Vesco and David Hatcher Childress. I
recommend it highly!
It chronicles the German investigations into all manner of MHD drives, mirroring Thomas Townsend Browns research in the US, culminating in Project
Winterhaven. There is discussion that Brown brought his research before the USAF prior to the war and was scoffed at, until the encounters with the
Foo Fighters during the war, which led the USAF to take Brown a bit more serious after the war.