Connections or airports visited on "milk runs" where I didn't leave the airport - most, of course, are current or former hubs. I should go see some of Atlanta, Houston, Dallas, and Denver someday, I guess...
* = didn't leave plane ("milkruns")
(only one outside the US!)
(milkrun, but we got to leave the plane)
** left the airport to go to/from a hotel after weather made miss my connections to BZE
. Other than the hotel and a Taco Bell across the street I saw nothing of Houston, so I count this one as an "in transit" even though I left the airport itself