I know the flight loads are much much lighter, but as a (somewhat) recent transplant from SEA to LAX w/ lots of DCA travel, I really miss the 2x daily frequency. If I want to fly AS, I'm stuck with a noonish LAX departure arriving at 9pmish, with a DCA departure of 9amish. Miss being able to work a full day in DC and hop a flight home. Given how frequently I'm seeing upgrades as a MVPG (even on 8 seat pmVX) on this route, I think it's a pretty good indication we're not likely to see a second daily added anytime soon.
