Here is an image of a plane that was never built. The Lockheed L-133 Starjet. The cool factor look of the plane is off the charts in my opinion. And the boldly ambitious design is amazing considering that it was drawn up in 1939. But coming from the people who would later run the Skunk Works perhaps it's not too surprising.
It was supposed to be powered by another perhaps even more ambitious Lockheed design the L-1000 engine. They were trying to build an axial flow jet that weighed about 1700 pounds and was going to produce about 5000 pounds of thrust. In 1940. If Lockheed had been provided with full funding and support from the U.S. government could this plane have flown in WW2?
Much more than the airframe it's the engine that was the biggest challenge. It was never developed but similar designs were by the late forties. If a successful axial flow engine of 5000 pounds thrust had been produced by the end of 1942 there would have been no shortage of airframe designs that could have been powered by it. But serious funding and effort would have needed to been applied to the L-1000 starting in 1939-1940 to get it worked up in time for service in WW2. That was an opportunity lost.
Lockheed did offer a proposal to the Army Air Force in 1942 to develop and produce the L-133 but the AAF declined. One can understand why. It must have looked impractically futuristic, like something out of a Flash Gordon comic book, to the worried and sober minded Generals in 1942. "Concentrate on building more P-38s", Lockheed was told.
The design seems overly ambitious for the period. The canard design was thought to be able to handle approaching the speed of sound better than a conventional planform. A good idea in a plane that was designed to reach better than 600 MPH in level flight at altitude. In a dive you would be approaching transonic speeds pretty quickly. Whether that canard shape was in fact an effective design choice considering in 1939 how poorly understood supersonic airflow was is a question.
And if in some ATL Universe it had been built and put into squadron service in 1943 than what?
What would have been the utility of a high performance but short-legged jet? It would have been the ultimate boom and zoom fighter for sure. But how useful it actually would have been would have depended on its range. The longer the range the more tasks it could've done. Perhaps the most important and range dependent being bomber escort in the ETO and the PTO. I have no idea on what the combat range of the L-133 Starjet would have been.