I think BWI to Philadelphia took about 20 minutes. Smallest was from Ft. Lauderdale to Andros Island. It seated 4.
MCI to Sedalia, MO on Trans Mo Airlines. Probably under 90 miles in a four seat, single engine (Cessna ?). I was the only passenger so I got to ride up front.
Chatted with the pilot for a bit, then he said he had to put his headset on to listen for ATC. Later I realized we were flying VFR and he was listening to an FM rock station.
I’ve flown from Seattle to Bellingham (and Bellingham to Seattle) a number of times, a distance of about 93 miles. Horizon Air gives (Gave? It’s been a while…) free local beer and wine. The cynical side of me says it’s to relax passengers who are nervous about flying on an airplane with propellers, but it’s probably just good marketing. After all, I’m posting about it now.
Port Townsend to Boeing Field, late 1990’s. Flights were frequently cancelled due to fog at Jefferson International Airport (snort). 4 seater not counting the pilot, a Cessna, I think. Also have flown from Port Angeles to Seatac in a Grumman with wings the size and shape of ironing boards.
My father was a couple thousand hour pilot, and since he started at 59, and built his own little hot rod Swearingen, used to embarrass me on these short flights as he’d ask to copilot ( :eek:)
In the mid-80’s I flew from Mt. Isa to Townsville (about 900km) but it was the ‘milkrun’ so it landed in each small town, making 5 stops along the way, each probably 120-150km apart.
This was on a Fokker F27 Friendship and there were only two of us as passengers for the first few legs. The stewardess gave me the safety briefing as my dad had flown in one a F27 before and I hadn’t 
My shortest flight was 38 minutes, from Fort Wayne, Indiana to Chicago.
Smallest plane I was ever on qualifies as commercial, I guess, because it was a tourist plane with a glass bottom that flew over the Grand Canyon. 17 passengers.
If you mean commercial as in, tied into the airport system and for transportation purposes only, then one of those commuter dealies with one seat on each side of the aisle.
:dubious:
Not being snarky, but a ‘glass-bottomed airplane’ might be a little problematic. Is there a chance you’re misremembering? If someone has modified an airplane with see-through floors, I’d like to have my ignorance fought.
Kalispell to Missoula, both in Montana, which took about an hour. I took this flight many, many times, when I lived in Illinois and Missouri and visited my relatives in Missoula (and nearby) more than yearly by flying Delta from St. Louis through Salt Lake City and Kalispell.