Yesterday, a little after 12:30pm EDT our system received its normal distribution of airfares (we are one of the handful of companies in th world that receive the raw airfare and rule information from ATPCO) and our email alert system processed the information and we noticed it sending out tens of thousands of price drop email alerts for a decrease in price.

Lately all we have seen is increases so this was certainly a welcome but odd occurrence. With further investigation we noted the amount of drop was quite large ($130rt for the most part — more on this shortly).

Here’s a sad story (well, sad if you’re the one of the folks who thought they’d pulled off the airfare deal of the century):

Irish airline Aer Lingus mistakenly sold business class flights to the U.S. for about $8. They blame a computer glitch; the flights should have been priced at about $2,800.

And, the airline says, no, it will not honor the $8 fares.

I’ve written about such mistakes, and it’s a murky area; from my personal experience here in the U.S., I know that some carriers will honor “mistake” fares, and some will not.

For the most part, the filing of airfare is completely automated nowadays and the airlines have gotten many of the kinks out of their systems that caused them periodic heartburn in years gone by.

Millions of airfare can and do change each day (we see this each and every day) and one would think this volume would be ripe for a ton of mistakes like the $33 business class airfare on Alitalia, from Toronto to Larnaca, Cyprus last year - but that isn’t really the case.

Many times $0 airfare isn’t necessarily a mistake — not in Europe, where airlines like Ryanair and EzJet periodically offer ridiculous numbers of “free” tickets (you have buy early, pack very light and not be overly hungry to get the best deal) –or in the U.S., where Skybus and Spirit Airlines regularly get great press on their sub $10 airfare. So, in the spirit of holiday fun, I thought it would be enlightening to review some mistakes we found (along with our alert users) this year:

Yes, sometimes airlines will actually post the wrong price and if you happen to notice it you can save an incredible amount of money.

In this case not only was Hawaii on Sale today, one airline filed many airfares for half the sale price (sounds like they coded one-way on the airfare incorrectly to me $223 rt vs. $445rt)

Airlines don’t make airfare mistakes very often, but when they do they can be whoppers and some lucky people are the beneficiary. Most people stumble upon good deals and mistakes — but this really doesn’t have to be the case.

The FareCompare.com email airfare alerts is based on technology that processes the raw fare and rule information directly from the airlines and sends it to you hours before it is even loaded on the airline sites.