I guess that in their spare time aircraft designers turn their thoughts to other things. A quick Google translation search says 'Tropfen' means a drop, as in 'rain drop'. Looking at the logo, I'd say that's pretty close, nicht wahr, Olham?
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Yes, "Tropfen" = "drop".
In early aerial dynamics studies they found, that a falling drop of liquid must have the perfect aerodynamic shape.
Reading in WIKI, it seems this Rumpler was the first of them all.

WIKIPEDIA - Rumpler Tropfenwagen

Your turn for a typo, old friend!

Damn - I am writing all crapp these days - the winter must have badly exhausted me.

This trend continued - Buckminster "Bucky" Fuller designed and built a teardrop shaped 3 wheeler in 1933, as can be seen here on YouTube. Marvelously maneuverable, but a fatal crash caused backers to pull out. Tricycle vehicles are notoriously unstable. I guess I should add that I realize that the Tropfenwagen wasn't a tricycle.

Anyway, I think that was about the last we've seen on teardrop cars. Now they all look like beans or roller skates.

Welcome to the club!