A senior aide to the prime minister is moving into a government affairs job with Air Canada, raising pointed questions about the strength of ethical rules governing the post-political lives of government staffers on Parliament Hill.

Derek Vanstone, currently Stephen Harper's deputy chief of staff, will become vice-president of corporate strategy and government affairs for the airline in September, Air Canada announced Thursday.

The airline's news release said the hiring "is subject to the approval of the Conflict of Interest and Ethics Commissioner, which has been provided."

Derek Vanstone has taken a job with Air Canada. (Twitter)

Conflict of Interest and Ethics Commissioner Mary Dawson's office won't release advice provided to public office holders, the name given to those covered by the legislation, without their permission, spokeswoman Margot Booth said in an email to CBC News.

Booth also pointed out that, despite Air Canada's contention that Dawson gave her approval of Vanstone taking the job, the ethics commissioner doesn't do that.

"We give advice to public office holders, but there is no requirement to approve job offers," she said.

"We always send a post-employment letter to reporting public office holders as soon as we are aware that they are leaving office."

Vanstone didn't respond to an emailed request for comment.

'Derek will be fully compliant' with restrictions

Both Air Canada and the prime minister's office said they were well aware of the ethical obligations facing Vanstone as he moves into the new role.

"Air Canada understands that there are a number of post employment restrictions for Derek with respect to federal government relations," said airline spokeswoman Angela Mah.

"Derek will be fully compliant with these restrictions."

Asked about the assertion Dawson had approved the hiring, Mah referred questions to Harper's office.

A spokesman for Harper said Dawson is the sole authority who determines whether or not officials are in compliance with the act. "Mr. Vanstone had lengthy discussions with the Office of the Ethics Commissioner and received their guidance in an email, which was later confirmed in a letter," Andrew MacDougall said.

After Vanstone provided information about the potential employer and his expected duties, Dawson's letter "confirmed that acceptance of this position does not contravene" the act, MacDougall said. "Mr. Vanstone certainly considers this to be approval. Certainly, if they had stated that acceptance of the offer would constitute a violation of the act, Mr. Vanstone would have considered this to be a prohibition."

Harper promised to close revolving door

The Harper government was elected in 2006 on a promise to build a stronger wall between ex-political staff and Parliament Hill. A slew of legislation followed, governing the activities of those seeking private sector jobs that could connect them with the government.

The hurdles Vanstone needed to clear to get the job include a five-year ban on becoming a registered lobbyist and a mandatory cooling-off period that prohibits involvement with any company with which he's had significant government dealings.

Air Canada has been engaged in an often bitter labour dispute with most of its unionized employees in recent months.

The threat of a lockout of pilots, and a strike notice from the mechanics and baggage handlers, had prompted the Harper government to intervene with back-to-work legislation in both disputes.

MacDougall said Vanstone was not involved in that legislation.

"Derek had no involvement with Air Canada on any aspect of Bill C-33 or any other legislation affecting Air Canada," he said.

Joanne McNamara, who had been serving as chief of staff to Canadian Heritage Minister James Moore, has been named to replace Vanstone in Harper's office.

Air Canada, government 'co-ordinate,' union says

The Air Canada Pilots Association said the appointment wasn't surprising.

"It's been evident to us for some time that Air Canada and the Harper government co-ordinate very closely," said ACPA president Paul Strachan.

"This appointment confirms that absolutely nothing has changed," Strachan said. "Certainly, it will present excellent opportunities for further co-ordination between the Government of Canada and the national airline."

Strachan said that Vanstone spoke on behalf of Flaherty's office in 2009 when a special pension funding protocol for Air Canada was negotiated.

Air Canada also said Vanstone wasn't involved in the back-to-work legislation, which was handled by Labour Minister Lisa Raitt.

"Derek had no involvement with Air Canada on any aspect of Bill C-33 or any other legislation affecting Air Canada," spokeswoman Isabelle Arthur said.

Vanstone will have responsibility for its relationships with all levels of government as well as community and industry affairs, Air Canada CEO Calin Rovinescu said in a statement.

"His solid experience and track record in the private sector and at the highest levels of government will further strengthen the management team's ability to execute our corporate priorities."

'Nudge-nudge, wink-wink,' critic says

New Democrat MP Charlie Angus, the party's critic on ethics files, said Thursday that this is an example of the old boys club at work.

"It's a nudge-nudge, wink-wink system that you have a senior advisor to the prime minister who just happens to be now coming back as the man opening the doors for Air Canada. This is what Mr. Harper said he would clean up, and he hasn't. In fact, he seems to have opened the door for his staff, for his friends to carry on like this. It's not acceptable."

Deputy Liberal Leader Ralph Goodale says Harper's chief of staff, Nigel Wright, was prohibited from dealing with Air Canada because of his previous work at private equity fund Onex. Wright led Onex's aerospace, defence, energy and transportation groups.

"Now saying that for the last year the deputy chief of staff didn't have anything to do with aviation matters, it leads you to [ask], well, who did?"

"From the public's point of view, it just doesn't pass the smell test," Goodale told Hannah Thibedeau on CBC News Network's Power & Politics.

Goodale told The Canadian Press his party will be writing to Dawson's office to request a detailed explanation for the ruling.

"She should explain to parliamentarians exactly how this is OK," Goodale said. "And if does fit within the law, most certainly there are exemptions or exceptions that should be plugged."

Ensuring compliance 'a challenge'

Dawson has raised issues with some of the provisions contained in the act before.

"...Ensuring compliance with the act's post-employment provisions remains a challenge," she wrote in her 2010-2011 annual report.

Her office acts in concert with the lobbying commissioner, who found earlier this year that another of Harper's deputy chiefs of staff had broken the rules. Karen Shepard concluded that Keith Beardsley broke a five-year ban on lobbying that applies to former public office holders.

Beardsley was turned in by Harper's then-chief of staff Guy Giorno.

A House of Commons committee recently recommended 11 changes to the Lobbying Act to make it stronger.

Vanstone will fill a role currently performed by Duncan Dee, who is taking early retirement. His departure, following 15 years with the airline, was announced on June 6.

Dee has been Air Canada's chief operating officer, a position that's often seen as second-in-command to the CEO and a potential successor to whoever is the chief executive.

Last month an arbitrator decided in favour of the airline in the case of the mechanics and baggage handlers, putting in place a new collective agreement.

The airline's 3,000 pilots are still in the process of working through their dispute with a separate federal arbitrator. A decision is required by the end of this month.

with files from CBC News