We are going September of this year and and flying out of Dallas. We have 2 airports: SW flies out of Love field (smaller & closer). The larger airlines, AA, Delta, United all fly out of DFW (much larger and about an hour from our house). I have been watching the airlines like a hawk since March and this is what I have seen.
I have found that Southwest best fares are as soon as they open their booking window (about 5 months in advance).
The day they opened their September flights On April 15 our flights were $116 each way, so $232. We thought those were great rates so we booked.
Now our flights on SW are $298 and have been that price or highter for a while (they seem to fluxuate alot.
AA flights are just the opposite. Their flights have been $350+ rt since they came out, until last week. Then on June 10th their non-stop flights (about the same flight times as ours) dropped to $248 rt non-stop.
When we weigh SW-closer, smaller airport w/no baggage fee's and 1 stop (no plane change) vs AA- larger, further away airport with baggage fee's and non-stop it is pretty much a wash onto which is a better deal.
If I look at cost alone, we are definitely saving at least $200 flying SW with the difference in flight cost and luggage fee's.
Now....when the Wright ammendment is lifted in October and SW is allowed non-stop flights from Dallas, SW should be the much better deal next year for our trip (as long as they don't jack up their prices).