Ryanair has cautioned over a hit from the move by a raft of online travel agents to remove the Irish airline from their websites.

The group said that, since early December, many of the larger sites such as Booking.com, Kiwi and Kayak have taken Ryanair off their sites.

It said the sudden removal from what it claimed were online travel agent “pirates” was “welcome”, but added that it would impact its so-called load factor, a key measure of how well airlines fill their planes, by 1% or 2% throughout December and January.

Revenues from tickets will also be affected in the short-term as Ryanair said it would respond by lowering fares for passengers booking directly through its own website.

But it said the move was unlikely to “materially affect” its full-year passenger numbers or profit expectations.

Its latest update showed it flew 9% more passengers in December, at 12.5 million, but its load factor fell to 91% from 92% a year ago.

More than another 900 Ryanair flights were cancelled last month due to the war between Israel and Hamas and the ongoing suspension of flights to Tel Aviv and neighbouring Jordan.

The update comes amid a long-running dispute between Ryanair and online booking sites, with the airline having launched legal action in the US against Booking.com owner Booking Holdings and its subsidiaries including Kayak, Agoda and Priceline.

Ryanair said it was not clear what the reason was behind its removal from the sites, but said it may be down to a recent Irish High Court ruling, which it said granted Ryanair a permanent injunction against screenscraper Flightbox from “unlawfully scraping Ryanair.com content” for online travel agents.

Screen-scraping involves a third party accessing an airline’s website and often offering the carrier’s fares to its own customers via its own site.

Ryanair said: “Ryanair will respond to this welcome removal of our flights from OTA (online travel agent) pirate websites, by lowering fares where necessary to encourage all passengers to book directly on Ryanair.com where they are guaranteed to always get the lowest air fares without OTA Pirate overcharges, fake contact info, or other pricing/refund scams.

“In the meantime, Ryanair continues to make its fares available to honest/transparent OTA’s such as Google Flights, who do not add hidden mark ups to Ryanair prices and who direct passengers to make their bookings directly on the Ryanair.com website.”

Booking.com and Kiwi were approached for comment.