Ju-86.

This is coolbert:

Before there was the American U-2 "spy plane" there was the German WW2 era Ju-86? Never heard of this before. Thanks to the Mark Felton You Tube video.

Think not so much the aerial combat but rather the capability of the Ju-86 reconnaissance warplane.

Ju-86 originally a bomber aircraft undergoing extensive modification and able to function as a photographic reconnaissance warplane operating routinely at altitudes of 50,000 feet [16,000 meters]. 

Comments:

* Personally it does amaze me an internal-combustion engine propeller-driven aircraft of any sort can operate at such high altitude and do so routinely. Such high-altitude flight capability I had thought only possible with the advent of the jet engine.

* Ju-86 on missions over England encountering the jet stream. Again, my perception and according to the best I knew the jet stream first experienced as a phenomenon by American B-29 bomber aircraft during raids over Japan in the most latter stages of WW2. That existence of the jet stream even more so understood very well by Japanese scientists even prior to the war but not known to American combat aviators.

coolbert.