The American version of Germany's "Vergeltungswaffe Eins" or V-1.
Initially the "buzz bomb" was known as the Fiesler 103.
Essentially a cruise missile, the V-1 carried a one-ton warhead and
used a pulsed jet engine to propel it at 360 miles per hour, at low
altitudes, toward such targets as London and Antwerp. The U.S.
version was not flown in WWII but was later used to test engine
technology and as a drone target.