Over the rest of the year, all aircraft in Southwest’s fleet will be retrofitted to accommodate the new seats with up to 5 inches of expanded legroom, the company said in a statement.

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