Easyjet has been slammed for an "utterly ridiculous" price hike after a Belfast passenger was quoted £860 for a return flight to Birmingham.
Claire Ewing tried to book a flight from Belfast International on Friday, March 20, to Birmingham, returning on Sunday, March 22.
Posting a picture of the booking page on Facebook, she said: "Airlines need a competitor or this is what happens.
"So much for serving the people of Northern Ireland. Charging £860 for a 'low-cost' flight from Belfast to Birmingham... utterly ridiculous."
This newspaper looked up a booking for the same flight with the airline and was quoted a price of £625.
Prices reduced substantially to £189 for a return flight with easyJet the following weekend.
The post from Ms Ewing followed the collapse of Flybe last week, which operated over 80% of the flights coming in and out of Belfast City Airport.
On Monday evening, more than a hundred Flybe workers gathered at Belfast City Hall to call for support from councillors.
Captain Chris Robb, base captain for Flybe at Belfast City Airport, said one friend from Southampton had been quoted a price of £700 to get to Belfast.
"We provided more than just an optional service. This country relied on it," he said. "If this is not addressed urgently, the whole economy of Northern Ireland is going to suffer immensely."
A spokeswoman from EasyJet denied prices had been artificially increased as a result of the Flybe collapse. "As with all airlines, our pricing is demand-led, which means that as more seats are booked on a flight the price will rise. Our fares start low and increase the closer it is to the date of departure," she added.
"The fares highlighted are a direct result of high demand for flights due to convenient scheduled flight times, so fares automatically increase as seats on the aircraft are booked. We do not artificially increase ticket prices.
"EasyJet currently has fares available throughout March from Belfast to Birmingham starting from £47.99."
On Wednesday afternoon, Flybe staff and supporters staged a protest at Stormont with chants of "save our airports, save our jobs".
Speaking ahead of the rally, Unite regional officer George Brash said 190 staff had been made redundant overnight.
The union is demanding that the Executive and airport authorities safeguard the long-term future of Belfast City Airport, connectivity and jobs.
He said that any airline seeking to take over Flybe routes could not cherry-pick but would have to agree to take on all routes and establish a base at the airport.
"Flybe's collapse resulted in a workforce here of 190 being made redundant overnight and posed a direct threat to the long-term sustainability of Belfast City Airport," he added.
"The airport plays a critical role in securing the economic connectivity of the metropolitan area. It also accommodates vital organ transit, the transportation of patients for medical treatment and allows family members to stay connected.
"The airport authorities and Stormont must ensure that any airline wanting to take on routes does not cherry-pick but commits to take them all on and establish a base at the airport. That's the only way to guarantee regional connectivity and jobs."
If this is not possible, Mr Brash called on the Executive to establish a public service airline to safeguard the route and the airport.
"Many airlines elsewhere in the world are run on a public service basis - why not here?" he asked.