“What has four wheels and flies?”/“A garbage truck.”

“What has four legs and flies?”/“A dead horse” is an old riddle. A popular variation of this riddle is:
 
Q: What has four wheels and flies?
A: A garbage truck.
 
The joke has been cited in print since at least 1926, when the answer was the “garbage wagon.” “Garbage truck” was given in a 1934 answer.
 
“What has one horn and gives milk?”/“A milk truck” and “What has 18 legs and catches flies?”/“A baseball team” are similar riddles.
 
   
Newspapers.com
30 March 1926, Pittsburgh (PA) Post, “In the Pittsburgh Theaters,” pg. 14, col. 1:
“What has four wheels and flies?—A garbage wagon.”
 
16 May 1926, Boston (MA) Herald, “Big Brother Says,” sec. E, pg. 8, col. 3:
What has four wheels and flies?
 
Old Fulton NY Post Cards
23 February 1927, The Evening Star (Peekskill, NY), “Communicated,” pg. 8, col. 4:
No doubt you have heard of The Happiness Boys spring this one. “What had four wheels and flies.” No, what is it. The Garbage Wagon. Very good.
   
Google News Archive
14 August 1932, Milwaukee (WI) Journal, “The Rambler,” Boys and Girls sec., pg. 2, col. 5:
Variation of an old riddle: What has four wheels and flies and is used to haul away garbage? Answer: A garbage wagon.
 
29 April 1934, The Sunday Star (Washington, DC), “Riddles,” The Boys and Girls Page, pg. 14, col. 4:
What has four wheels and flies?—Catherine Bauer
A garbage truck.
 
OCLC WorldCat record
What has four wheels and flies? : a tale.
Author: Douglass Wallop
Publisher: New York : Norton, ©1958, 1959.
Edition/Format:   Print book : Fiction : English : 1st ed
 
Google News Archive
28 April 1970, Washington (DC) Afro-American, “Riddles,” magazine sec., pg. 2, col. 2:
What has four wheels and flies?
A garbage wagon.
 
Google News Archive
20 June 1977, The Free Lance-Star (Fredericksburg, VA), “Fun Time—The Riddle Box,” pg. 22, col. 2:
What has four wheels and flies?
A garbage truck.
 
Google Books
Comedy High and Low:
An Introduction to the Experience of Comedy
By Maurice Charney
New York, NY: Oxford University Press
1978
Pg. 21:
Sometimes the questions go in series, with an ascending (and possibly off-color) climax. “What has four wheels and flies? A garbage truck.” “But what has four legs and flies? Two pairs of pants.”
 
Twitter
James Hofheins
‏@jwhof
What has four wheels and flies?  A garbage truck.
1:10 PM - 23 Sep 2008
 
reddit
What has four wheels and flies
submitted June 25, 2015 by manu1287
A Garbage truck
COMMENTS
Smokerscoff
My first thought was a delorean. But i like the joke.
 
PinguinRS
I was thinking of two grannies flying off from a cliff.. yeah messed up i know..