The story
Unknown, early 20th c.. A book titled "At the Front in a Flivver" was published in 1917. Cartoonist Tad Dorgan in 1919 claimed to have created the term in his comic strip Judge Rummy.
Etymology from Wiktionary, CC BY-SA 4.0.
flivver
Today it means: An automobile or cart, particularly one which is old and inexpensive. Full definition →