The Canadian Union of Public Employees is challenging Labour Minister Patty Hajdu in Federal Court, accusing her of overstepping her authority by halting a legal strike by 10,500 Air Canada flight attendants. The union argued Hajdu’s order trampled workers’ constitutional rights and undermined collective bargaining.In a court application obtained by Blacklock's Reporter, CUPE lawyers argued Hajdu “exceeded her powers” when she invoked section 107 of the Canada Labour Code, which allows the minister to act to preserve “industrial peace.” The filing claimed her directive effectively nullified the charter right to strike.Hajdu issued the order Saturday, only three hours after picketing began. Cabinet has now used section 107 to end seven strikes in the past year, the most ever in such a short period..The union alleged the minister’s repeated use of the clause has emboldened employers to walk away from serious bargaining. “Air Canada ceased bargaining on August 12 and instead shifted its focus to requesting government intervention,” CUPE wrote. The airline presented Hajdu with a brief urging her to block the job action before it began.Despite the ban, flight attendants continued to strike until a settlement was reached yesterday. CUPE is asking a judge to declare Hajdu’s decision unlawful and to rule that cabinet’s reliance on section 107 violates freedom of association rights under the charter.Hajdu has not filed a response, but over the weekend told reporters she disliked strikes, calling them “very disruptive” and costly for workers and companies. She rejected suggestions her government is anti-union, saying the decision was about “industrial peace and the safety of Canadians.”