TORONTO (Bloomberg) — Air Canada, the country's biggest airline, and other carriers can't charge disabled or obese people for an extra ticket when they need an additional seat or an attendant to accompany them.

The Supreme Court of Canada yesterday refused to hear an appeal from the airline, upholding a Canadian Transportation Agency ruling, the first of its kind in the world, ordering carriers to charge all passengers the same fare and not make people pay extra when they need an additional seat for medical reasons.

Air Canada, its Jazz unit, and WestJet Airlines Ltd., the Canada's second-biggest carrier, failed to prove the policy would impose undue hardship on them, the transportation agency said in its ruling in January. The agency estimated the change would cost Air Canada, which reported C$10.6 billion in revenue last year, C$7.3 million ($5.7 million) annually.