It's the Great Pumpkin, Charlie Brown(1966)
Linus seems to be the only one who believes in the magic of a Great Pumkin who chooses the most sincere pumpkin patch in the world to rise out of and spread gifts to good little boys and girls all over the world. To all the other kids, Linus is out of his "gord". But that doesn't deter Linus. Linus sacrifices tricks, treats and a fun halloween party to come face to face with The Great Pumpkin. But there is one person who believes young Linus. The one person with a hopeless crush over him, young Sally.