Bob Hoover

Via Posthip Scott. This is the second time I have seen a Twin Mustang.
    I saw Bob performing at the local air show with his Aero Commander once. I wasn't particularly impressed. I mean it didn't have nine zillion horsepower, or roar like a freight train, or break the sound barrier. On the other hand he was doing stuff you wouldn't expect out of a midget airliner. This preview prompted to me to look him up on the net, where I found this amusing little clip.

Bob Hoover Barrel Roll

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Update January 2021 replaced missing 2nd video.

F-82 Twin Mustang

From a post by mrsekt on Military Photos dot net:

It looks like something a kid would dream up, but they really built them. They were too late to participate in WW2, but they proved to be quite effective in the Korean War.

From Wikipedia:

"On 27 February 1947, P-82B 44-65168, named Betty Jo and flown by Colonel Robert E. Thacker, made history when it flew nonstop from Hawaii to New York without refueling, a distance of 5,051 mi (8,129 km) in 14 hr 32 min. It averaged 347.5 miles per hour (559.2 km/h).
[...]
To this day, it remains the longest nonstop flight ever made by a propeller-driven fighter, and the fastest such a distance has ever been covered in a piston-engined aircraft"

P.S. Note that the record is for "a propeller-driven fighter", not a propeller-driven airplane.