“What’s the difference between a politician and a flying pig?”/“The letter F.”

A political riddle went viral in November 2016 (around the U.S. presidential election):
 
Q: What’s the difference between a politician and a flying pig?
A: The letter F.
 
The “lying politician” joke was posted several times on Twitter on July 20, 2010. The joke appears to have started in the United Kingdom, and then was popularized in the United States when it was posted on Reddit on November 10, 2016.
 
   
Twitter
Kam
‏@ShishaWorld
What’s the difference between a politician and a flying pig?
The letter F.
10:02 AM - 20 Jul 2010
 
Twitter
Bonky
‏@mitmot
What’s the difference between a politician and a flying pig? The letter F !! “”
http://sn.im/almurray
12:15 PM - 20 Jul 2010
 
Twitter
Andy Webb
‏@webbyand
What’s the difference between a politician and a flying pig?
The letter F.
4:55 PM - 20 Jul 2010
   
The Sun (UK)
You’ve got to feel Perky when the Trotters are on TV
BY TAM COWAN 25th September 2015, 7:55 am
(...)
PS. While we’re on the subject, what’s the difference between a politician and a flying pig? The letter ‘f’ . . .
 
Reddit
What’s the difference between a politician and a flying pig?
submitted November 10, 2016 by FourWordReplies
The letter F
 
The Huffington Post
37 Jokes To Make You Feel Better About That Sh*tshow Of A Week
It’s been rough week folks.
11/11/2016 19:00
(...)
What’s the difference between a politician and a flying pig?
The letter F
r/Jokes FourWordReplies