You do appreciate that like an encyclopedia a dictionary can only report the usage of yesterday, when it's compiled (although online compilation does provide contemporary updates). The accelerated dynamics of the contemporary world adds thousands of words, good and bad, annually. Emplane and deplane have far longer histories of usage than terms we've been quick to accept, such as "texting", or the current media fascination, "sexting".

As much as i cherish the marvelous words and usage of the Bard of Avon and still re-read and appreciate the somewhat turgid usage of Winston Churchill's HotISP, I suspect that neither would have had any problem appreciating the usage of "debark", "emplane" and "deplane".

Some "new" words don't make it beyond the narrow parameters of their application. "Corpen", a special sort of turn, remains meaningless to but a few, specific and meaningful to the rare breed who use/have used it. I'll let you go to the effort of determining its validity and existence.