Air New Zealand's (NZE:AIR, ASX:AIZ) group capacity fell 4.6% year on year in September due to aircraft availability, according to a Thursday filing with the New Zealand bourse.

Long-haul international available seat kilometers (ASKs) dropped 6.6%, short-haul international ASKs declined 0.8%, and domestic ASKs were down 4.2%.

New Zealand's flagship airline carried roughly 1.5 million passengers in September, down 7.3% from 1.6 million passengers a year ago.

Year to date, Air New Zealand carried 3.9 million passengers, down 4.3% on the year-ago period.

The airline's shares were up nearly 2% in recent trade.