Plans for a second airport in Auckland have taken flight today.

Air New Zealand's confirmed it's working on plans to fly some domestic routes from Whenuapai, which it says will help save passengers money.

Early modelling shows services to Wellington and Christchurch could be commercially viable, and the airline's also considering flights to Queenstown, Napier, Nelson and Palmerston North.

The airline says once it has a firm proposal, it will urge the Government to consider the options.

Chief executive Christopher Luxon says a second airport would keep travel costs down.