Oh, he's probably getting ready to take off in his Sopwith Camel on the next dawn patrol.
6 seconds sound clip from the It's the Great Pumpkin, Charlie Brown (1966) movie soundboard.
You can hear this line at 00:13:16.340 in the Blu-ray version of the movie.
Quote context
[...]
- By the way, whatever happened to the World War I flying ace?
- Oh, he's probably getting ready to take off in his Sopwith Camel on the next dawn patrol.
- His mission is to find the Red Baron and shoot him down.
- Here's the World War I flying ace climbing into the cockpit of his Sopwith Camel.
(plane motor sputtering to life and revving)
[...]