Irish low-cost carrier Ryanair will cut its London Stansted Airport traffic 9% over the coming year in response to a charges hike by outgoing owners Ferrovial/BAA. The move would reduce Ryanair’s passenger traffic from 12.5 million passengers to 11.4 million.

Ryanair claims that—prior to the handover of the airport to new owner Manchester Airport Group (MAG) Thursday—Ferrovial/BAA announced that Stansted airport charges would increase 6% from April 2013.

Ryanair called on the Civil Aviation Authority (CAA) “to investigate whether this unjustified and unwarranted 6% price hike was a ‘sweetener’… to persuade MAG to pay £1.5 billion ($2.27 billion) for Stansted.” The airline suggested the price was disproportionate in view of the fact “that Stansted’s traffic has declined from 24 million passengers a year to just 17.5 million over the last six years.”

Ryanair said it had planned to grow Stansted traffic by 5% from April 2013, but instead would now cut frequencies on 43 routes and reduce weekly operations by more than 170 flights, at a loss of 1.1 million passengers. This, it said, would translate into 1,100 job losses at the airport.

Ryanair spokesman Robin Kiely said, “It’s bad enough that Ferrovial/BAA has doubled prices over the past six years and presided over record traffic falls at Stansted.” He said it was “impossible to understand” why the previous owner had raised charges when it would no longer be running the airport.

“The CAA must now investigate the reasons for this price increase and take action to protect Stansted users from this latest example of price gouging from Ferrovial/BAA,” Kiely said.

MAG said it was too early to comment on the planned charges increase or any course of action it might take.

An MAG spokesman said: “As part of our plans to grow passenger volume at Stansted over the short, medium and long term, we will continuously engage with all of the airlines that operate there, many of which are already valued customers of ours.”

MAG said it had “a detailed integration plan in place to ensure a seamless transition of ownership and operations at Stansted.”