The media buzz around airlines introducing basic economy fares has been strong—although a bit misconstrued. These “basic economy” fares are designed to compete with the onslaught of low-fare airlines like Spirit and Frontier that are slowly encroaching on the turf of legacy airlines like American, Delta, and United.

Airlines say these fares offer customers more choice (which they do) and lower airfares, but the reality is that airlines are not necessarily lowering airfare further. The basic economy moniker is simply being slapped on what were already the airline’s lowest fares (often reduced to match the competition). In fact, passengers are forced to now pay more for services they were once getting for free from legacy carriers, like seat assignments and carry-on bags.

These fares are only suitable for those willing to endure fewer amenities than before, unless you travel light, don’t chase elite status, and don’t mind the middle seat.

Surprisingly, not all basic economy fares are created equal, and elite fliers on some airlines are getting a better deal than those on others. Here’s what you need to know about each carrier’s basic offerings.

American’s Basic Economy

American’s basic economy fare is being introduced in certain markets this month (Minneapolis/St. Paul is one of the initial cities), then rolled out to other markets gradually. It will be made very clear on the airline’s website that you are purchasing this “no-frills” ticket, but when booking elsewhere, it is important to identify the fare class. If it is “B,” then this is basic economy.

B class still includes free nonalcoholic drinks and access to the airline’s onboard entertainment programming (streamed free via mobile devices or laptops).

What these fares do not include is a large carry-on bag. The media has reported that B-class fliers will not be allowed to use overhead bins; however, this is untrue. While carry-on bags for basic economy fares must fit underneath the seat in front of you, customers can still use overhead bins if there is space once other passengers have boarded.

Similar to the policies of other airlines like Allegiant and WOW Air of Iceland, standard rollaboard bags are not allowed on this fare. Basic economy customers must pay to check them at the ticket counter or incur the same charge plus a $25 service fee at the gate.

American has been generous to its elite fliers with this fare (as it should be to its most loyal fliers). Frequent fliers get a carry-on bag waiver and can continue to bring on one personal item and standard rollaboard in addition to checking bags for free. Their carry-on bags can be placed in the overhead bin like the personal items of other passengers. Travelers with American Airlines cobranded credit cards will also enjoy this perk.

And unlike basic economy passengers, who will be assigned to board in the last group, elite fliers can continue to enjoy priority boarding. All passengers can still earn miles on these fares but get dinged in the elite-qualifying categories where earnings are reduced by 50 percent.

Elite fliers are not eligible for any type of upgrade or advance seat assignment (get a seat at check-in or buy one 48 hours before departure), and no one, regardless of elite status, can change or refund the ticket. Use it or lose it.

Delta’s Basic Economy

Delta pioneered the fare in the market (it’s been in place for more than a year) and launched it with a few more perks than its competition. Fliers can still bring the standard carry-on allowance, although they cannot select seats in advance or make changes or request refunds to their tickets. They are also treated to free soft drinks and snacks plus the airline’s free inflight movies and TV programming (something not offered on Allegiant, Frontier, Spirit, or even Southwest).

Elite fliers can still receive priority boarding and free checked bag allowances, plus earn the standard mileage bonuses for the ticket, but they are not eligible for upgrades. They also can only select seats at check-in, and elites can’t buy a better, more-legroom seat—even at the airport.

Delta.com makes it clear that you are booking this bargain basement fare, but on other sites, be sure to look for “E” class tickets.

United’s Basic Economy

United’s announcement was the real shocker because it was the first to announce the limited carry-on baggage allowance. Many media reports misrepresented overhead bin use; customers can still place their small personal item like a backpack or purse in the overhead bin if there is space once everyone boards. Basic economy fare customers cannot take a standard carry-on bag, however; it must fit underneath the seat.

Like American and Delta, United waives the carry-on restrictions for its elite members, Star Alliance Gold fliers, and cobranded credit cardholders, who also still enjoy priority boarding. But the airline is the most restrictive when it comes to elite mileage earning, which is zilch. All fliers still earn regular miles, but nothing that will advance them toward maintaining frequent flier status.

No passengers can make an advance seat assignment until arriving at the airport when they purchase a basic economy ticket, which means that even the airline’s most frequent customers could get stuck in a middle seat with no option to upgrade. United’s fares will begin flying this spring, and it says it plans to make the basic economy fares very clear online so customers know what they are buying.

Does it make sense for frequent fliers or families?

Loyal fliers may find that the basic economy fares are not worth it unless the flights are very short since perks like advance seating, elite mileage earning, and upgrades are reduced or taken away completely. Delta is the most generous in this regard, allowing fliers to still earn full mileage. United is the stingiest, offering its elite fliers nothing more than a carry-on bag and mileage earning (not elite-qualifying) while American meets its elites in the middle.

If your flights are on regional jets, there aren’t any middle seats so you can risk it without a seat assignment. But if you’re traveling with children, these cheapest fares may not be for you since there are no advance assigned seats. New government regulation is in the works to require that children under 13 are seated with an accompanying adult, but this has yet to be instituted.

What seems short-sighted on the part of airlines is that many business travelers are mandated by their companies to purchase the lowest fare. The reason travelers rush to maintain elite status is for the perks, no matter how small. Basic economy nixes that for a lot of people, which could risk sending some fliers into the arms of Southwest or other low-fare airlines if schedules are more convenient.

Airlines have succeeded at not only muddling up the understanding of earning miles but now they also have confused customers when it comes to buying a ticket. It pays to do your homework before clicking purchase, and remember that sometimes, cheaper is not always better.

>>Next: How to Rack Up Even More Points and Miles This Spring