The most expensive bundle in Southwest's new fare program will be Choice Extra, which will also include the most add-ons as part of the base fare. Choice Extra ticketholders will get early boarding, two free checked bags and complimentary access to extra legroom seats at booking and complimentary internet.

Southwest Airlines announced four revamped fare bundles after recently ending its signature free checked bag and open seating policies.

But, as TPG first reported last fall, Southwest customers won't have to wait until then to start seeing the more spacious rows on certain Southwest flights. Rather, they'll start appearing on planes months before the airline's open-seating setup ends — and that will begin May 1.