Some would cite the F104G Starfighter as 'developed' by Lockheed for the Luftwaffe, but 'just look at the shape of this beauty':
So in terms of aesthetics and recorded death rate per mile, easily the worst aircraft ever built (you can't really call it an aeroplane!) - the Flying Flea:
'... the original HM.14 revealed design flaws that could lead to an unrecoverable and often fatal dive under certain conditions; when the front wing was put in a high attack angle for climbing, the high-speed flow of air deflected by the front wing went to the rear wing upper surface, greatly increasing the rear wing's lift, and putting the nose down, the instinctive reaction of pilot being pulling even more the stick, this worsened the situation, as the way to go out of this 'vicious circle' was reducing the front wing incidence, as to command a nose down descent. Also some homebuilders attempted to simplify construction by modifying components such as the wings tips curving up, resulting in extremely dangerous airplanes and deadly accidents that forced the air authorities to ban building more of them'