"I think it's appropriate he stays in the business advisory council role for that period ... Once he departs, we'll find a replacement at that time."
She had no concerns about whether Luxon might run for the National Party in the future.
"Obviously he has a role still to fulfill at Air NZ and I imagine his mind will rightly be on that through to September."
She said Luxon called her yesterday to give her notice about the announcement of his resignation, but they mainly discussed the advisory council.
Luxon, who has been at Air NZ for seven years, hinted at a move into politics in the statement he released last night.
"I would like to think more about how I can best use my skills, abilities and experience to make a further contribution to the success of New Zealand whether that be through corporate life, politics or a not for profit," Luxon said.
This morning he said he had "compartmentalised" the decision and was focused on finishing his time at Air New Zealand before looking to the future.
He said he was not "John Key 2.0", but said on the AM Show that the former Prime Minister and Air NZ board member had encouraged him to stand for National.
"We've talked about it obviously, at some sort of level. He's an encouraging sort of guy - I mean, I know him pretty well.
"He's encouraging of any good people that want to get into politics. It's just a conversation we've had over the years."
Luxon said it was not an issue to indicate support for National while serving on the business advisory council.