Air New Zealand's (NZE:AIR, ASX:AIZ) group capacity dropped 1.2% year on year in December impacted by lower aircraft availability due to maintenance requirements, according to a Wednesday filing with the Australian and New Zealand bourses.

Long-haul international available seat kilometers (ASKs) decreased 3.8%, short-haul international ASKs grew 3.7%, and domestic ASKs were down 1.1%, the filing said.

The country's flagship airline carried over 1.6 million passengers in November, down 0.6% on the year-ago period, per the filing.

Year-to-date, the number of passengers carried was down 2.1% to nearly 8.1 million compared with 8.6 million in the prior-year period.

The airline's shares were up nearly 1% in recent Wednesday trade in New Zealand.