I think the one underlying reason that makes SWA a true LCC is that the top cap on fares, the last minute wlk up fares, are only 299.00 plus taxes. The post above shows that. All of those fares are within $18. I do not have a clue what you pay on F9 for a last minute purchase, but my friends in Denver tell me that they are high. They welcome SWA for their last minute business travel but say that they will stick with F9 when they can plan ahead.