This one really surprised us when we found it. It appears to be an advertisement concept for "Jaco Pastorius". Someone - probably Jaco - thankfully crossed out the image, and most likely nixed the promo (if you look closely, you'll see the big black "X" through the top image).

The image itself has handwritten words across the top: "Take a Ride on Jaco's Rocket Ship", and there's some space travelers holding the album (hand-drawn in this proof), watching Jaco's bass zoom by.

The promo copy at the bottom reads:

"Jaco Pastorius doesn't just play bass. He's redefining the instrument with a conception so astounding that other bass players and even guitar players are being left far behind.
Jaco is wowing 'em live with Weather Report. And now he'll amaze you with his first solo album "Jaco Pastorius."
Jaco's taking the bass into outer space. On Epic Records and Tapes."

This actually could have been the prototype for what actually became the promo insert for the solo album, which you can see here.