Monkey,
Luf has it right on the nose, "Kennscht mi noch?" is pretty much along the lines of "Do you know me now?".
If I'm not mistaken, this is either a funky dialect from the period which has now fallen into disuse (it really won't translate properly, say, if you use most of the translation software out there) or it was slang that also is no longer in use.
Either way, I don't recall having learned any such phrase or similar phrases when I took German in school. Although I do recall learning the word "mi" from my first teacher as a sort of slang word. She was old enuff to possibly have been around (if only as a child) shortly after the Great War.
Anyhoo, Kempf is the name of the pilot of that Dr.1. With his name written across the wing in big 'ole white letters, I can understand the "Kennscht mi noch?" as being either sarcasm or morbid humor. Preferably, if I'd been him, I wouldn't have wanted an enemy to gain such a position as to be able to read it!
![Tongue [:P]](/FSM/CS/emoticons/icon_smile_tongue.gif)
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