“Law of Airlines: The shorter the time between flights, the greater the distance between gates” is an airport saying that has been printed on many images. “The shorter the time between flights, the greater the distance between gates” was written by American columnist Doug Larson (1926-2017) in the Green Bay (WI) Post-Gazette on August 15, 1990.
     
“Law of Airlines: The shorter the time between flights, the greater the distance between gates.—Doug Larson, United Features Syndicate” was printed in The Reader’s Digest in 1996.
   
                       
Wikipedia: Doug Larson
Doug Larson (February 10, 1926 to April 1, 2017) was a columnist and editor for the Door County Advocate (1953–1964) and wrote a daily column, “Doug’s Dugout,” for the Green Bay Press-Gazette (1964–1988), both Wisconsin-based newspapers. The column was originally syndicated through United Media under the title “Senator Soaper Says”; Larson took over authorship in 1980. Previously, it had been written by Bill Vaughn of the Kansas City Star. Larson was born in Sturgeon Bay, Wisconsin.
     
15 August 1990, Green Bay (WI) Post-Gazette, Doug Larson column, pg. A-7, col. 1:
The shorter the time between flights, the greater the distance between gates.
 
10 September 1990, St. Louis (MO) Post-Dispatch, “Senator Soaper,” pg. 8D, col. 2:
The shorter the time between flights, the greater the distance between gates.
   
24 May 1996, Detroit (MI) Free Press, “It says here that sayings hit home” by Ernie Harwell, pg. 7C, col. 2:
The shorter the time between flights, the greater the distance between airport gates. 
 
Google Books
The Reader’s Digest
Volume 148      
1996
Pg. 22:
Law of Airlines: The shorter the time between flights, the greater the distance between gates.
—Doug Larson, United Features Syndicate
     
Google Books
Ernie Harwell:
My 60 Years in Baseball
By Tom Keegan
Chicago, IL: Triumph Books
2002
Pg. 49:
The shorter the time between flights, the longer the distance between airport gates.
(...)
—E. H. June 1994
 
Google Books
Wise Quotes of Wisdom:
A Lifetime Collection of Quotes, Sayings, Philosophies, Viewpoints and Thoughts
By R.A. Wise
Bloomington, IN: AuthorHouse
2011
Pg. 177:
RULES – Law of Airlines: The shorter the time between flights, the greater the distance between gates. –Doug Larson
 
Twitter
Coach Lord
@SkipLord
“Law of Airlines: The shorter the time between flights, the greater the distance between gates.”
- Doug Larson
5:53 AM - 9 Mar 2017
 
Twitter
PhoenixRising
@nicratwoman
Law of Airlines: The shorter the time between flights, the greater the distance between gates.
Doug Larson
8:43 PM - 11 Jul 2018