Ryanair has warned it plans to cut the number of flights to and from UK airports by 10% next year.
The Irish low-cost airline has just celebrated its tenth anniversary at Cardiff Airport, providing a number of European routes.
But according to chief executive Michael O'Leary, the decision to increase tax on airline tickets in the Budget this week will "make air travel much more expensive" and hampers the UK's "growth prospects".
Chancellor Rachel Reeves insisted her decisions will "fix" the economy's foundations.
But Ryanair has condemned the increase of £2 per passenger on short-haul low fare air travel, claiming it would hit regional airports in particular.
Mr O'Leary said: "This short-sighted tax grab will make air travel much more expensive for ordinary UK families going on holidays abroad and will make the UK a less competitive destination compared to Ireland, Sweden, Hungary and Italy where these governments are abolishing travel taxes to stimulate traffic, tourism, and jobs growth in their economies."
Cardiff Airport said Ryanair's direct flights had attracted more than 685,000 passengers since launch in October 2014.
Currently, the airline runs five routes linking Rhoose with Faro, Alicante, Malaga, Tenerife and Dublin.
Ahead of Ryanair's announcement on Friday, Spencer Birns, Cardiff Airport chief executive, said: "It’s amazing to see so many of our passengers enjoying the advantages of using Ryanair flights at our airport."
"People living in Wales have great choice of popular destinations at low prices, thanks to Ryanair’s growth over the years. We’ve seen huge demand from our customers for more low-cost travel from their national airport."
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