A relentless advocate for airline passengers' rights in Canada was in court Monday, arguing that his complaint about allegedly discriminatory practices against "large" passengers shouldn't be thrown out just because he himself isn't large or obese.

Gabor Lukacs, whose dozens of complaints against the airline industry have resulted in numerous policy changes, complained in August, 2014 that Delta Air Lines was discriminating against larger passengers by refusing to let them on flights for which they had confirmed reservations, and forcing them to take later flights. He also complained about recently implemented airline policies that require those passengers to buy additional seats to avoid the risk of being denied transportation.

The Canadian Transportation Agency, a government regulatory board, found he lacked private and public standing in the matter and dismissed the complaint.

The airline argued, as summarized in the agency's decision, that "given that Mr. Lukács is lighter than the average Canadian, despite being slightly taller, it is patently clear that he does not have a direct interest in the subject matter of the proposed complaint and his rights are not affected by the impugned practices nor would he suffer any prejudice if he elected to travel with Delta."

"In this case, we're dealing with a matter that protects the collective interest of the travelling public at large, and not simply individual interests. It doesn't matter who the complainant is — it could be anybody."

Lukacs had filed the complaint after he was sent a copy of a letter that Delta had sent to a passenger after they filed a complaint to the airline about the discomfort they felt, sitting beside a larger passenger. The letter included an apology to the customer, described measures the airline takes to "help make a large passenger, and the people sitting nearby comfortable, and offered the complainant a $50 Delta gift card.

"Sometimes, we ask the passenger to move to a location in the plane where there's more space. If the flight is full, we may ask the passenger to take a later flight. We recommend that large passengers purchase additional seats, so they can avoid being asked to rebook and so we can guarantee comfort for all," the letter said.

The letter struck Lukacs "as something so inappropriate, so obviously contrary to common decency" that he expected little opposition from the Canadian Transportation Agency, he told VICE News. But the proceedings have now dragged out for two years "since the agency started messing around with some technicality instead of actually addressing the merits of the matter," he said.

Lukacs appealed the board's decision, and now the legal battle is moving forward.

Arguing before three judges of the Federal Court of Appeal on Monday in Nova Scotia, Lukacs said that dismissing the complaint because it didn't affect him as an individual was like dismissing a meat factory worker's complaints about contaminated food just because it didn't make them sick.

"In this case, we're dealing with a matter that protects the collective interest of the travelling public at large, and not simply individual interests," he said. "It doesn't matter who the complainant is — it could be anybody."

The judges will deliver a decision in the coming months.

If they do, in fact, find that Lukacs' complaint is valid, it wouldn't be the first time that the courts have gotten involved with an airline service issue.

In 2014, the Supreme Court ruled that Air Canada had violated the language rights of two French-speaking passengers, after they ordered a 7up in French, only to receive a Sprite from the English-speaking flight attendant.