A Quebec Superior Court judge has authorized a class action lawsuit against Air Canada over fuel surcharges.

The lawsuit, approved yesterday, argues the country's largest airline "illegally overcharged its customers" by more than double for the cost of fuel on some flights.

The legal action claims Air Canada misrepresented the stated purpose of the surcharge, which was to partially offset the fluctuating price of jet fuel.

Michael Vathilakis, the petitioner's lawyer, cites one example in which Air Canada allegedly charged business and economy passengers 105 per cent more than the fuel cost on a flight to Paris in January 2014.

The lawsuit says each economy passenger on that flight paid $238 in fuel surcharges alone -- $163 more than they should have according to Air Canada's contract definition of the charge. It says the airline took in $73,878 in fuel supplements on the flight, rather than the $23,164 it should have charged.

Vathliakis claims that some clients were charged a fuel surcharge that was more than the cost for the fuel for the entire flight.

The suit states Air Canada's contract with consumers allows it to charge them within a 33 per cent variation in the cost of fuel, based on price history and adjusted for inflation.

McGill University professor John Gradek is an aviation industry analyst and held a senior management role in operations, marketing and planning at Air Canada, and said the lawsuit puts action behind many customers' suspicions about airlines.

"It's another example of airlines being perceived by the travelling public as charging too much for their air tickets," he said. "Whether it's baggage or whether it's seat charges or whether it's fuel surcharges or taxes or whatever it is you pay, the tax load you have when you buy a ticket is significant."

If airlines are willing to add extra charges, Gradek feels lawsuits like the one filed will ensue.

"People are saying, 'Why am I paying that? What value do I get out of all of those taxes?' Any chance that people or organizations have to challenge those taxes, they will, and this is just another example of that," he said.

Air Canada released a statement responding to the suit.

"We disagree with these allegations, and we intend to vigorously defend our position through the courts," the statement read.