The Airline Pilots' Association is carrying on with its legal fight over Wellington Airport's controversial runway extension.
It lost in the High Court last week but today told the airport it would go to the Court of Appeal.
An airport company spokesperson said it was surprised and disappointed with the appeal plans, because the High Court's decision backing the company was emphatic.
The association had argued it wasn't consulted properly over safety zones at the end of the 350m runway extension into Cook Strait, which has been estimated to cost $300 million.
The extension's economic viability has been debated repeatedly, with opponents saying it will never make money and supporters saying it will earn back its investment - and more.
The airport said it, and the Civil Aviation Authority, which had approved its plans, would participate in the union's appeal.