Airfare is a crapshoot at best. There are so many factors that it is impossible to predict.
If you are firm in your days and times, it is best to book when you see something within your budget. If you are looking at NWA, if the prices go down, they will issue you a voucher.
SWA may come in cheaper, but keep in mind that it usually means for a longer flight and stops. I found some great cheap seats on SWA this past Easter, but it also meant a stopover in Chicago and a plane change in St Louis, which made the whole trip down 6.5 hours! Coming home it was the same thing, a plane change in Nashville and a stopover in Chicago before landing in DTW.
If anything, I see airfare going UP. The airlines are cutting flights and flying with fuller planes. There is really no need to cut to the bone.
pin
remember the magic
DVC/BCVs 2002