One of the best tools to find great airfare deals used to be the ITA Matrix. It had several useful features that allowed users to search for airfare between city pairs over several months using flexible date ranges for the duration of your trip, making it a great resource for finding some of those low-cost mileage run deals.The ITA Matrix has been one of the most useful airfare search tools out there.The one major downside is that you cannot book airfare directly through the Matrix but instead must go to an airline or online travel agency website to price out the ticket and buy it. Still, that was a small price to pay for some truly amazing deals that were to be found.However, the folks on this FlyerTalk thread have noted that in recent months the ITA Matrix seems to be going downhill fast. Whereas before, you could use the Matrix to search for airfares with numerous criteria like fare booking classes, searching specific airlines and specific alliances, and even displaying a price per mile. You can find out the command functions for doing so here.And here is an example of what it looks like when you click on the “Advanced Routing Codes” link to enter in the commands for the particular criteria you would like.Lately, though, people seem to have been finding that any effort to use these more advanced search options leads to a search timeout at about 60 seconds.Among the faults that they identify are:Search timeoutsIncorrect pricing that you cannot replicate through OTA’s or specific airlinesSearching using “Nearby” airports up to 500 miles awaySearching by alliance stalls the searchSpecifying fare codes or routing rules stalls the searchFor a quick example, here is a calendar of availbility in April for roundtrip flights between New York JFK and Frankfurt:It prices out no problem on a variety of dates, and then pulls up specific flight options:And then you can go book it on a site like Orbitz:Sign up for our daily newsletterEmail addressSign upI would like to subscribe to The Points Guy newsletters and special email promotions. The Points Guy will not share or sell your email. See privacy policy.However, if you try to expand the search to nearby airports like this:The search stalls for a while and then you get the following error message:So it looks like the ITA Matrix is losing some of its functionality for the hardcore deal-searchers out there. While you might have issues searching specific fare classes and airlines, however, if you are just looking to price out simple airfares between city pairs over date ranges, the Matrix should still be useful.Here are some things to keep in mind:Search specific airportsSearch specific dates when possibleSearch “normal” date ranges (like 3-10 days) if you are looking at an availability calendarLook at the airline options that are pulled up and go to the site where you are most likely to get the same results, whether it is an airline or OTAHave any of you been having trouble using the ITA Matrix lately? Share your experiences in the comments below.