Can You Explain Airline Pricing?

For several months, I've been monitoring airfares from Knoxville and nearby airports such as Asheville and Tri-Cities to Springfield, Missouri. I will be attending a conference for librarians there this summer. Springfield is apparently one of those destinations where one can rarely find a "deal." Most of the time, the pricing was about the same. The cheapest rate I'd been able to find was about $457 out of Knoxville (without taxes and fees). The cheapest rate from Asheville had been over $500 and out of Tri-Cities over $600. Having frequently checked to see if prices had come down without seeing any changes, I had just about resolved myself to the fact that I was going to have to rent a car and have a two day drive each way with an overnight stay. Then Saturday night I decided to check fares again. I checked Knoxville first and found that I could get a flight for $352. I checked Asheville and discovered it was only $292. I decided that I'd better go grab the credit card before they decided to go up on me. I had several options for departure from Asheville flights at the $292 rate, but the only option I had for a return flight was one with two stops. I decided that I could deal with the two stops and booked it! It beats a two day drive! Out of curiosity, I checked the rates again Sunday evening. Guess what? The cheapest flight out of Asheville was now $391 and the Knoxville price was similar for the airline I'll be flying; however, there was still one airline with the cheaper rate which was still about $60 more than I'm paying. I count myself fortunate to have gotten in that window of opportunity for the reduced pricing! I don't understand how airline pricing works. It makes no sense how a fare jumped nearly $100 overnight.