I was not paid or compensated in any way for this post. The comments below reflect my own opinions and experience.
The United States does not do discount airlines like Europe or other parts of the world. Every time I fly, or am just online dreaming of flying, I truly miss Ryan Air, Easy Jet and Pegasus Airlines. A few times last year, I ran across Spirit Airlines which flies from Baltimore to Dallas where we have family. Frankly, it seemed a little too good to be true so I never used them. Then earlier this year we needed a last minute flight and I was able to book a flight for $34. That is not a typo. Even with the bag that I needed for this trip, the final cost was $64. The return flight cost more, and with the bag was $103.09. Total round trip cost was $167.09 with less than 7 days advance purchase (the first flight was purchased less than 12 hours prior)
This was a no frills airline but frankly other than the baggage limitations, the experience was not significantly different than any recent trip on a US major airline.
That said, there have been other times I have gone to use them and frankly they are as expensive or even more expensive than other carriers. And since those other airlines allow a checked bag or a carry-on and fly out of Reagan National (DCA) I have gone main stream more often than not.
Their website is difficult to use to find a good deal if you are just looking to go “someplace” and I haven’t taken the plunge and paid to become a member. But bottom line: They have some great domestic and international destinations and are adding new routes all the time. If you live somewhere they fly (DC, Vegas, LA, Denver, Minneapolis, Dallas, Orlando, Tampa, Miami, Boston, Detroit, Chicago, or Atlanta) they are worth checking out. I have found this to be especially true if buying last minute tickets and not able to buy 7-14 days in advance. The ride is comfortable and if the price is right I love the idea of supporting the other guy to improve the market and provide us with more travel options!
Travel tip: For those that hate to pay the baggage fees like I do, consider just a small carryon bag. For example, for visiting family we keep an extra set of toiletries at their house. This one time purchase was less than the cost of one bag, lasts for several trips and helps us travel light and fast.