A Quebec judge has authorized a class action lawsuit against Air Canada on behalf of obese travellers who had to pay extra because of their disability during a three-year period ending in December 2008.

The Montreal law firm BGA Barristers & Solicitors LLP announced the ruling on Monday. David Bourgoin, a lawyer with the firm, said a similar suit against WestJet was thrown out because of a technicality, but the firm has about 30 days to fix the problem and continue the case against WestJet.

The case against Air Canada is aimed at reclaiming fees the airline charged obese passengers for a second seat or a seat for an attendant before a tribunal and court ruling outlawed the practice.

In January 2008, the Canadian Transportation Agency ruled that Canada's major air carriers — Air Canada and WestJet — must offer a single fare to those with disabilities, including the severely obese, who require two seats to accommodate them. The ruling also said people with disabilities did not have to pay extra for medical attendants who must be seated with them on flights.

The agency estimated the requirement would cost Air Canada about $7 million a year and WestJet about $1.5 million a year.

In November 2008, the Supreme Court rejected an application by the two airlines for permission to appeal the tribunal's ruling, which had the effect of upholding it.

Justice Catherine La Rosa of the Superior Court of Quebec gave the go-ahead to the class action on Oct. 3, BGA said in a news release.

The lawyers said the action was launched on behalf of "all persons domiciled in Canada who are disabled or recognized as having a functional disability by reason of their obesity who had to pay additional fees to Air Canada for the seat of an attendant and/or for a seat adapted to their condition on a domestic flight operated by Air Canada or by another carrier on its behalf between December 5, 2005 and December 5, 2008."

Bourgoin said the parallel case against WestJet was thrown out because the plaintiff who represented the class did not qualify as a member of the class. BGA has to find a qualified representative within about 30 days or the case will expire, he added.