Airfare booking
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Cheap flights reveal themselves in a number of ways — JetBlue’s limited run flash sales, $187 round-trip flights from the United States to Africa, and even as all-out airfare wars.

At Travel + Leisure, we’re always on the lookout for unbeatable flight deals. After all, what inspires travelers to get up and go faster than $383 round-trip flights to Italy?

But not all cheap flights are the same. Some are only bookable through the airline with a special promo code, while others are accidents — and can disappear even after you’ve booked them.

Whether we’ve pointed you in the direction of a great flight deal, or you’ve stumbled upon one on your own, knowing the difference between an internal promotion and an error fare can help you determine where to book, how to book, and when to start planning your vacation.

Flash Sales

To encourage travelers to book directly with the airline, carriers will discount flights or offer a limited number of cheap seats. Emirates, for example, regularly runs 2-for-1 sales (think: $799 round-trip for two tickets to Milan), while the Irish budget airline, Ryanair, might sell 100,000 tickets for less than $6. Thrifty Traveler calls this your “traditional fare sale.”

Airline-sponsored sales typically have restricted travel dates, a curbed number of available seats, and rigid cut-off times for purchase.

While it’s not uncommon for airline sales to yield small savings, the promotions can occasionally be massive. In November, for example, Spirit Airlines offered 87.1 percent off flight bookings to celebrate on-time arrivals.

Travelers who are interested in predicting airfare sales should be on the lookout during holidays (Black Friday fares are not uncommon) and make note of regular airline promotions. Every June and October, for instance, Southwest Airlines runs a 72-hour sale.

Airfare Wars

There may be no better example of a full-on airfare war than what’s happening on Hawaiian routes right now.

It started when United Airlines announced a massive route expansion to the Aloha State, offering travelers new ways to fly to Hawaii. As we predicted, competitors like Hawaiian Airlines were forced to drop their prices.

Since then, both Hawaiian and Alaska Airlines have expanded their services and lowered ticket prices. And with Southwest announcing an intention to enter the Hawaiian market, it’s likely flights will continue to get more affordable.

In December, flights to Hawaii dropped to $179, thanks to increased service from Hawaiian Airlines.

What’s happening in Hawaii can also take place over a much shorter period of time. Thrifty Traveler noted that in the event of a “share recapture,” an airline can lower ticket prices in another market to impact an airline adversary — an often localized and short-lived event — or a brief fare war in which an airline attacks another carrier’s hubs by lowering flights from those specific airports.

Mistake Fares

Impossible to predict and one of the most lucrative ways to save on airfare, mistake fares (sometimes called error or “fat finger” fares) are ticket prices that seem too good to be true.

Round-trip flights from the United States to Australia for $509, for example, or First Class flights to London from the West Coast for $1,522 round-trip are two examples of accidentally published fares.

They occur when a misplaced decimal point, miscalculated currency conversion, computer glitch, or data entry error turns a $2,594 Business Class seat into a $594 Business Class seat.

Thrifty Traveler noted that these outrageously cheap tickets appear less frequently than ever, as airlines are increasingly cautious about preventing these accidents.

Mistake fares are incredibly short-lived, because they disappear as soon as the airline notices what’s happening. And because airlines are no longer required to honor mistake fares, tickets can be canceled even after booking.

For that reason, travelers are encouraged to wait until the ticket has been issued to make any additional travel plans, like hotel or tour reservations. When an airline rescinds mistake fare tickets, they’re required to reimburse the purchase, as well as all out-of-pocket expenses incurred by the traveler in confidence of the reservation.

Whether you’re looking for a squeaky-clean promotion or a once-in-a-lifetime mistake fare, follow your preferred airlines on social media, check flight deal-hunting websites like Thrifty Traveler, Scott’s Cheap Flights, the Flight Deal, and the Airfare Spot, and sign up for airfare alerts with Airfarewatchdog or Hopper to see prices plummet on your favorite routes — and make sure you never miss a cheap flight of any kind.