Cassels-Brown said the flags will be flown for the entire duration of the second flag referendum.
Auckland Airport is one of many businesses and CEO's embracing the country's opportunity to change the flag.
Air New Zealand CEO Christopher Luxon said the changing the flag is New Zealand's opportunity to create a unique international identity.
Luxon has said that Kyle Lockwood's blue, black and white silver fern design is his favourite.
"For me, the silver fern has great symbolism. If you think about how Maori used it for guiding and illuminating pathways through the forest," it can be interpreted in a modern way to guide us all home, he said.
Businessman Lloyd Morrison sparked discussion on changing the flag in 2004, when he commissioned a simple black and white block fern.
The second flag referendum will be held later this month and will decide on New Zealand's future flag.