Key point: The Komet remains the only rocket-powered fighter to have entered operational service.
Nazi Germany pursued numerous ambitious and impractical weapon programs over the course of World War II. One of the few that saw action was the Messerschmitt Me 163 Komet, the only rocket-powered fighter to enter operational service. The stubby rocket planes were blindingly fast by the standards of World War II fighters—but were in as much danger of blowing up from their volatile rocket fuel as they were of being shot down by enemy fire.
The quest for more powerful propulsion systems is as old as the history of aviation. While development of the first turbojet engines began in the late 1920s, other designers were drawn by the potential of preexisting rocket technology. Unlike air-breathing turbojets, rocket motors rely operate solely on propellant, and can deliver greater thrust—with the limitation being that they burn through propellant really fast.
The first aircraft to fly under rocket power was actually a modified tail-less glider, the Ente (“Duck”) produced by German designer Alexander Lippisch. Lippisch began working with glider-manufacturer DFS on a proper rocket fighter in the late 1930s, before transferring his DFS 194 prototype to the Messerschmitt airplane manufacturer. Because Messerschmitt had worked on an observation plane called the Bf 163 before switching to using “Me” aircraft designations, the designers figured using the Me 163 designation would trick Allied intelligence as to the rocket plane’s true nature.