While other airline Frequent Flyer programs seem to all require LONG advance purchase/redemption in order to obtain the BEST deals on using your free flights, SW, instead, lets you pretty much use your voucher right at the counter! Fortunately, I was able to fly to attend a funeral w/understandably no advance notice. I have points on many other airline programs. But, SW was the only one that let me fly, with no "last minute fees"! I HIGHLY RECOMMEND THEM!