"Luftkissenboot" is "air pillow boat". I think those who say "Luftkissenfahrzeug" ("air pillow vehicle") might also be those who say "Fernsprechhandapparat" ("long distance speech hand(held) device") instead of "Hörer" ("(phone) handset").

:-)

But my favorite is "Personenvereinzelungsanlage" (people turn-into-singles device, aka turnstile). It describes very clearly what it does, but not how it does it. Whereas turnstile is silent regarding whether it works or not.