It’s the Great Pumpkin, Charlie Brown
Linus is getting ready for his yearly trip to the pumpkin patch to greet the Great Pumpkin. He talks Sally into waiting with him, but their paths are crossed with Snoopy, imagining himself as a World War One fighter pilot trying to find his way home.
A Halloween special, it was the third Peanuts TV special (and second holiday-themed special, following A Charlie Brown Christmas)
Plot summary: IAD