This is a real sign, and is one of my favorites from the Harrison Mayes collection at the Appalachian Museum in Norris, Tennessee. See here for the very interesting story about this gentleman. And here is another blogger who posted about Harrison Mayes.
NOTE: P.A.E. stands for "Planetary Aviation Evangelist" (!! ;-)
One thing you have to say about this guy -- when he made a promise, he did his best to keep it.
(Sorry to be so brief -- I'm actually working on some real job stuff tonight. Sigh.)