DEN-BZN, just under 2 hours on a 737.

Of course, I always fly out of a hub (IAD) so this dismal record is to be expected. Did much, much better in the days of the 500 mile certs (as has been discussed to death by many).

Then, again, two years ago we (Ms. Portolan and I) got an OpUp LHR-IAD which was worth quite a few domestic F upgrades.