Join Date: May 1998
Location: Reno, NV (RNO)
Programs: AA LT Platinum, AS, UA Premier Silver, DL, HHonors Gold, Marriott LT Titanium, Hyatt, IHG Platinum
Posts: 4,723
OK, the South African Air run between JFK and LGA is a bus so it doesn't count.
The shortest run (with a plane) for any of the routes mentioned so far is MIA-FLL at 21 miles. It is served by a commuter plane, not a jet.
ITH-ELM is 32 miles and US actually runs a DC-9 jet on one of the flights.
WRG (Wrangell) to PSG (Petersburg) along the Inside Passage is served by an Alaska Air 737. It is only 31 miles.