high school mascots with a vehicle theme

Norwalk truckers! (thanks Marc!)

Speedway Sparkplugs

(in Washington state) the Richland Bombers (mural on their gym)

Richland, as part of the Manhattan project, was as important as Los Alamos and Oakridge to our nuclear strategy. It produced the plutonium for "Fat Man" -- the atomic bomb dropped on Nagasaki. After World War II, it continued to produce much of the fissible materials for the US nuclear weapons. Further, it was and is the dumping ground for much of the United States' nuclear waste.

Their motto is "proud of the cloud"

the above, is a Hesston Swather. So is the below, to give some idea of WTF this is all about

The Hesston Swathers take their name from the farm implement that's still made in their central Kansas town. A swather is sort of like a combine, but different. Here's what the Merriam-Webster dictionary has to say: "A swather is a harvesting machine that cuts and windrows grain and seed crops; also: a mower attachment that windrows the swath."

and after more than nine decades as the Kingsford Flivvers, Breitung Township schools finally have once they get to call their own. http://www.ironmountaindailynews.com/news/local-news/2017/10/proud-to-be-a-flivver/

 Clyde Fliers, St Paul Flyers, and Lake Flyers (thanks Marc!)