There are many claimants to the term, but the most widely held has to do with an activity that once occurred a great deal near the Flatiron Building, located on 23rd St., at the intersection of 5th Ave. and Broadway, in Manhattan. It seems that the odd-shaped building causes the wind to swirl around it. In the 20s, men would gather around to watch as the wind would cause the ends of women's long skirts to fly up and reveal their ankles, a rare sit back then. The local constables would run the men off, giving them the "23, ski-doo." It so happens, that 23 was already part of the vernacular as a slang expression that meant there was no reason to hang around (from various sources). As the Flatrion Building was on 23 St., giving someone the "23, ski-doo" became the surviving variant of "23, skedaddle." Skedaddle means to move or run away quickly.
I could not find any connection of the expression to any automobile.
I hope this helps and thank you for an intriguing question.
This answer was edited by Peanutbred 780 days ago.
Reason: Typo
