An airline and an online travel agent are suing a 22-year-old computer programmer who created a website that searches out “hidden” air fares.

The companies involved - United Airlines and Orbitz - are seeking more than $75,000 in damages.

Aktarer Zaman created Skiplagged to help expose “pricing inefficiencies for air travel”.  The website does this by exposing cheaper stopover airfares.

The BBC uses an example of a flight between New York and Lake Tahoe with a stopover in San Francisco. Using Skiplagged the passenger might find this route is cheaper than buying a direct ticket between the two cities. This approach only works with hand luggage, as anything checked in would continue to the final destination.

However, the two firms launching the legal action are unhappy with what they allege is “unfair competition”. They also argue that Zaman has “has used his website to intentionally and maliciously interfere with Plaintiffs’ contracts and business relations in the airline industry”.

The legal documents have been filed in the US state of Illinois.

Zaman is not giving up without a fight. He has setup a donation page on the website gofundme with the aim of raising $60,000. So far he has raised almost $49,000.

“Hey everyone, thank you so much for your generous donations! As a 22yr old with a startup being bullied by these large corporations, your support means so much to me,” he said in a post.