Canada's largest airline is trying to figure out which obese and disabled passengers will be eligible for additional seats at no charge after the country's Supreme Court rejected an appeal by the airlines. The Canadian Transportation Agency issued an order last January requiring Air Canada and other domestic airlines to make additional seats free to disabled or obese passengers who need extra room. The airlines' appeal was rejected twice - first by the Federal Court of Appeal in May, and then by the country's highest court last Thursday. Air Canada spokesman Peter Fitzpatrick said Monday the airline was developing detailed eligibility rules for free seats. The ruling Thursday applies only to domestic flights and will be implemented January 9, 2009. "It's been basically left to the airlines to determine how they are going to comply," Fitzpatrick said. "We're working on it now." Under the ruling, airlines cannot charge extra for an obese person who needs an additional seat or a disabled person who needs space for a wheelchair or stretcher or who must be accompanied by an attendant. David Baker, the Toronto lawyer who fought the case on behalf of disabled passengers, said the ruling will allow more disabled people to travel. Joanne Neubauer of Victoria, one of two people whose complaints sparked the case, said the news made her feel like "an equal citizen in this country." Neubauer suffers from rheumatoid arthritis and uses a motorized wheelchair. Air Canada and WestJet, Canada's second-largest carrier, said they would comply with the Transportation Agency's order. WestJet spokesman Richard Bartem said his company might consider extending the policy to international flights. Bus, train and ferry companies have long made arrangements for free extra seats, but the airline industry had argued it would lose too much money by doing the same. The Transportation Agency rejected claims that providing extra seats would impose an "undue hardship" on airlines, saying they could afford the financial burden. The agency estimated the cost to Air Canada at about $7 million Canadian ($5.6m.) a year and to WestJet at about $1.5 million Canadian ($1.2m.) a year. The agency said that amounts to about 77 cents Canadian (62 cents) a ticket for Air Canada and 44 cents Canadian (36 cents) for WestJet. To put it another way, the agency said the cost would be 0.09 percent of Air Canada's annual passenger revenue and 0.16% of WestJet's revenue.