I do think that on balance especially on advance purchase fares B6 has lowered rates in this BOS DCA market; especially now that they have ramped up flights. With US for a while being the sole or nearly sole carrier, the fares were outrageous even if booked in advance. I have also read that typically when B6 enters markets it lowers fares more than Southwest.

Also back in the day there used to be a lot of competition on this route with US, NW, and DL at least flying it. You could get roundtrip tickets for a while using a Delta promo for $100 including taxes, and it wasn't uncommon for roundtrips to be $125 to $150.

When US was the near dominant carrier, fares were a lot less to IAD and BWI; but now it has stabilized and it really doesn't save you much if any money to fly to BWI or IAD.

Also I suppose even for the non Mosaic flyers they are getting 1 free checked bag for now, and they are getting less than the $200 change fee that would be charged by a legacy and they can go standby at no charge on the immediately preceeding flight. Where as US would charge them the Move Up fee.

I would also like to know the strata of people on this route i.e. how many people fly it every week, every month, etc. break downs like that. Or on most flights how many Exec Plats or Mosaics are there? I find that on US on standby or the upgrade list as an Exec Plat I am 99% of the time #1 on the list
http://mobile.usairways.com
so I'm wondering if there are not many Exec Plats or old Chairman's on the route; I mean its hard to qualify with 100 or 120 segments!