Another Warner Brothers military film rediscovered: The Cartoon Brew site discusses this film: cartoonbrew.com/classic/grampaw-pettibone-by-warner-bros-cartoons.
Much lesser-known than the Pvt. Snafu, cartoons for the Army, the Grampaw Pettigrew character was thought to have been created by the UPA studio for Navy training films, but Brew researchers found the first of these was definitely Warner Brothers, probably Frank Tashlin directed, definitely Carl Stallings music.
Start of the cartoon has some rather limited animation, though it carries the precautionary tale well: a bomber pilot so focused on his bombsight while diving toward his target, that he forgets to check his altimeter, and blam! To we who are many years removed from the war, the sequence evokes the Rebel X-Wing pilots trying to sight that thermal exhaust port on the Death Star. If only that pilot had trusted The Force.
The other half of the film is said Grandpa (an aircraft mechanic?) lecturing the audience about carelessness. One gets the impression that someone higher-up might have thought Pvt. Snafu getting killed in humorous ways from his own ineptitude was taking the vital message they wanted to convey too lightly.
Side note: "Grampaw Pettigrew" was created by Robert Osborn, who illustrated thousands of posters and other educational materials for the Navy. There's an appreciation of him here: www.cartoonbrew.com/comics/the-largest-on-line-stash-of-robert-osborns-dilbert
He main educational creation was a screw-up Navy pilot named "Dilbert," which soon became the slang term for screw-up throughout the Navy, and which Scott Adams has said was where he got the name for his comic strip from. Another trivia trifecta for today!