"It's all about providing options," Delta spokesman Paul Skrbec said.
The markets where Delta is testing the basic economy fares are those where Delta faces competition from Spirit Airlines. That low-cost carrier has gained notoriety for its bare-bones ways, offering some very low fares but charging extra for even carry-on bags.
With Spirit, "you're buying the right to sit on an airplane on a flight, and everything else will cost extra," said Brett Snyder, author of the blog crankyflier.com and a former airline manager.
Delta's basic economy fare does not allow any changes to the itinerary, even for a change fee. It also does not allow passengers to get seat assignments in advance. Instead, seats are auto-assigned at check-in.
Delta has said the basic economy fares may be expanded to other markets in the future, but has not announced anything on if or when they might come to Atlanta.
A sample of fares for flights from Detroit to Fort Lauderdale for July showed economy fares for $248.60 and basic economy fares for $229.60.
The fares are designed for "the most cost-conscious type of customer," Skrbec said. The inability to change the itinerary could be the largest surprise for passengers who book a basic economy fare without paying attention to the limitations, and think they can change their flight if they run into an emergency. For most fliers, missing a flight could require a $50 fee to take a later flight, as with regular fares.
In the past few months, Delta also started selling "trip extras" during the flight booking process, including priority boarding starting at $9, 1,000 extra frequent flier miles for $29, and a one-day pass for in-flight Wi-Fi Internet access for $12. Separately, Delta sells an upgrade to seats with more legroom called "economy comfort" and other "preferred seats." And other options Delta has added include selling "premium meals" to coach class passengers in advance on certain cross-country flights from New York and allowing travelers to "flex" their fare by making it refundable.
"The basic idea is to get people to pay for what they want, instead of the previous one-size-fits-all type of fare," Snyder said. "Before, there was always this assumption that if you were flying, you wanted to check bags and you wanted to eat on the airplane and you wanted a seat assignment. What the airlines have done is they've started peeling that back."
Snyder compared the tiers to cable packages, such as those that include cable, extra channels, phone or Internet service.
Other airlines have sold fares in tiers for a number of years, including Air Canada and Denver-based Frontier Airlines.
And carriers like Delta will be "dipping their toes into it to see if it's a model that works for them," Snyder said, "and I think it's going to be something that people should expect to see more of."