If you’re a dedicated reader of these blogs (OK, Mom, I’ll include you as well), you’ve seen several articles in the past few months about the “Big Three” airlines’ (American, Delta and United) new marketing approach of offering “extra” low fares.

First, a brief history of these new fares . . . they were actually torn from the playbook of the ultra-low-cost carrier Spirit and their stripped-down airfares. You know, the airline that almost all corporate travelers loathe. Spirit Airlines offers extra-cheap ticket prices with few perks and plenty of restrictions that force travelers to pay extra for seat assignments, carry-on bags, and so on and so on. It’s a business model that business flyers love to hate, but one that has made Spirit Airlines very profitable, as well as a darling of Wall Street.

Of the Big Three legacy airlines, Delta was the first to embrace the concept, introducing Basic Economy fares to compete with Spirit on routes where the two carriers compete. As of today, Delta offers Basic Economy on 60% of its domestic routes, and expects to expand coverage to 100% of its entire domestic network by mid-year.

The other Big Three airlines, American and United, recently put their own versions of unbundled fares on sale in select markets. By the end of this year, unbundled fares will be widely - if not universally - available on all legacy carriers for U.S. domestic flights.

Travelers are always suckers for low prices, and that’s what Basic Economy is all about. But it’s also about restrictions that can make for a less comfortable flight experience, and surcharges that can make the final price a shocker.

Just a reminder to all those travelers who may not be familiar with these new fares, the fares cannot be exchanged or changed, period. You either fly on that particular flight or you lose the total value of the ticket. What’s even worse, if you miss your initial flight (outbound), your return is voided. You lose 100% of the value of the ticket. You cannot check baggage, even if you are willing to pay $50. You are limited to one carry-on bag and that will cost you $25 (ladies' purses excluded – can you smell a lawsuit brewing?). These restrictions also mean you will earn no frequent flyer points, and you will be issued a middle seat. Additionally, you will be the last boarding group (Beginning April 1, American Airlines is going to nine boarding groups. Nine! Guess where basic fare passengers end up?).

As a side note, TravelPlex will not offer these fares. Your company has requested these fares be blocked from Concur Travel (if your company utilizes Concur) as well as any fare offered by a travel Counselor. Your company knows these fares fall outside the TravelPlex Low Fare Guarantee.

If you have any questions about these new fares, please contact TravelPlex for additional clarity.