I don't think the weekend fares start out more expensive on weekends. I think the weekends the cheap fares just book up fast. I also fly out of MHT and some of the times I've flown weekends are the same as weekdays and other times weekends are more expensive as they show unavailable (meaning sold out) for the cheapest fares or the best times have already gone up in price. It doesn't take long for the weekend lowest rates to become unavailable. For my next trip, we're leaving on a weekday, but returning on a Sunday over the holidays so I'm going to be Johnny on the spot early June 23 getting my return fare (that's when SW opens their fares past Oct). I can always get a credit if the rate goes down but I figure that day will book up VERY fast.