Mr Mulligan instead took public transport from the Blue Mountains to the Gold Coast to visit sick and bereaved relatives.

But after a five-year dispute and two court cases, Virgin has been forced to pay him $10,000 as compensation for the pain and distress he suffered. The Federal Court ruled Virgin unlawfully discriminated against Mr Mulligan by preventing his dog from travelling in the cabin.

Mr Mulligan first told Virgin he wanted to fly with Willow in 2010, saying he suffered from vision, hearing and mobility problems. The airline said he could not take Willow, then changed its mind, then reverted to its original decision.

Mr Mulligan sent Virgin documents from rail authorities, a doctor and a dog training association to show he needed an assistance dog and that Willow was properly trained.

But Virgin said that under Civil Aviation Safety Authority regulations it needed evidence Willow was trained by an approved organisation and had passed a "public access test".

Mr Mulligan said as a result he was forced to catch buses and trains when travelling interstate to visit relatives. A medical report from Dr Denise Baker in January this year said he was "no longer able to cope with travelling long distances by road or rail". Mr Mulligan told his doctor he was rising at 3am and travelling up to 22 hours in a journey.

He took Virgin to the Federal Circuit Court in 2013, alleging unlawful discrimination on the basis of his disability. But Judge Sandy Street agreed with Virgin that it was simply obeying the law.

On appeal, the Federal Court found numerous errors in Judge Street's interpretation of the air safety regulations and how they interacted with the Disability Discrimination Act.

In a unanimous verdict, three judges said: "Although the airline is entitled to request evidence that Willow is an assistance animal and that she is trained to meet standards of hygiene and behaviour...that training need not be by an accredited organisation."

"It's an important case and we welcome the finding," Age and Disability Discrimination Commissioner Susan Ryan said.

"What it establishes is a person who wants an assistance animal for the purposes of flight can't be denied a seat for that reason."

Ms Ryan said the commission continued to receive "quite a few" complaints about the way businesses and transport operators treated assistance animals.