Plan 9 From Outer Space - A Little Help from the Flight Attendant.
When the flight attendant walks into the cockpit on the second Airplane/Cockpit scene you can see the Co-pilot look directly at the flight attendants clipboard. You can also see the flight attendant hold the clipboard at an angle when ever the Co-pilot says a line.
Bacon: you didn't make it perfectly clear, but if you were referring to the fact that the "actors" didn't know their "lines" & had to read them off the clipboards (which they did) then you're right, this is quite a hilarious slipup! Still, i gotta wonder if it's at all necessary to post slipups from Ed Wood films - seems kinda redundant - his whole career was a slipup!