An airline has given a traveller forced to sit next to an overweight woman a full refund. Picture: Flickr user Tobyotter

Janet Ogilvie said she was faced with the awkward situation on a Porter Airlines flight from Halifax, Canada to Ottawa on September 5 this year.

Ms Ogilvie said she went to her seat to find an obese woman, who was assigned to a window seat, spilling over into half of her aisle seat, the Ottawa Citizen reports.

She claims the woman's spine was where the middle armrest comes down, and the woman also needed a belt extender to buckle up.

With no other empty seats available, Ms Ogilvie wedged herself into the 25 centimetres that were left of her seat for the one hour and forty-five minute trip.

She said she was essentially sitting on her right hip the entire journey.

"I couldn't put my left shoulder back because she was there... I was pressed up tight against her for the whole flight," Ms Ogilvie said.

Porter Airlines initially refused a refund when she complained about the situation, offering her a $100 credit card voucher instead.

"It was a terribly unpleasant experience, made worse by the fact that Porter is basically saying: 'That's your problem, not ours'.

"I don't think it's my problem that I paid for a seat and Porter gave it away to this other person."

However Ms Oglive continued to protest the situation, eventually winning a full refund of $200.

Porter Airlines Chief Executive Robert Deluce promised her that the airline's crew will be better trained "to proactively assess and immediately attempt to rectify any situation that could lead to what you encountered".

The debate over overweight people and airline seats has raged for years, with a survey by Travel.com.au showing that 70 per cent of Australians believe that the obese should have to buy two seats when flying economy.

While some airlines are forced to give passengers who are disabled by their obesity two seats for the price of one, carriers can refuse to accommodate those who show up at the airport without giving prior notice of their requirements or may put them on another flight.

Australia's main airlines don't force obese people to pay for two seats, despite similar policies being adopted by international air giants United Airlines and Air France-KLM within the last year.

A spokeswoman for Virgin Blue said most overweight people are aware if they don't fit into one seat and will often purchase two seats to ensure their own comfort.

"There is no formal policy, however if a guest does not fit into a seat on a full flight they will be moved to the next available flight,'' she said.

A spokeswoman for Qantas said the airline did everything it could to meet the needs of overweight customers.

"Should a customer require extra space on a flight we seat them next to an empty seat where possible,'' she said.

"However the only way for a customer to guarantee extra space is to either purchase two economy seats or fly business or first class.

"But we have no plans to implement anything that would force them to do so.''

In-depth: All the latest travel news

Follow our Twitter blog

Follow our travel reporter and travel editor's Twitter blog