Thanks for all the feedback. It's interesting, because what works best from one city as to the destination airport may work differently from a different city.

Case in point: Beckles example. The dynamics of MSY-DAY are different than those present on IAH/HOU-DAY. The low fares present are as a result of AirTran flying the route (from HOU and MSY) and some carriers matching their fares, and others not matching. Here in Houston, CO recently initiated non-stop service to DAY and they do not match AirTran's fares when there is no Sat. stay, on either CO's non-stop or connecting service. DL, however, does match the fare from both Houston and New Orleans. My feeling is that DL is hell bent on running AirTran out of business because AirTran has significantly cut into DL's profits out of ATL.

These same dynamics are in place in Efrem's example of MHT-IAH vs. BOS-IAH on connecting service. CO, on the other hand, charges about $1,750 on the BOS-IAH-BOS no Saturday stay fare because they are the only carrier providing non-stop service on the route.

Interestingly, MHT and PVD used to be a great alternative on CO from IAH with no Saturday stay, but no more. Even though both CO and WN now offer non-stop service between PVD and Houston, CO does not match WN's non-Sat. stay fares. IAH-BOS is an extremely lucrative route for CO and they aren't going to allow those profits to be hit by business travelers flying to either PVD or MHT.

Southwest's long history of profitability and reliable service has shown that no matter what the majors do on competing routes, WN will survive and do well. AirTran, OTOH, is still in a state of flux, revising routes every few months and could clearly, IMO, be incapacitated by DL primarily, and the other majors on their competing routes. Once AirTran is no longer a player in the market, fares will skyrocket. So Efrem, keep your fingers crossed that AirTran continues to serve BOS-ATL, or you won't be seeing BOS as a low fare alternative to MHT.