OTTAWA — The Canadian Union of Public Employees (CUPE) has initiated a lawsuit against the federal government, seeking to prevent the use of a controversial legal measure that was employed to end a strike by Air Canada flight attendants. The lawsuit, filed on Monday, highlights CUPE's strong disapproval of both the airline and the Liberal government.

CUPE, which represents over 750,000 members, including the striking flight attendants, claims that Jobs Minister Patty Hajdu violated the constitutional right to strike by invoking section 107 of the Canada Labour Code. This section allows the minister to direct the Canadian Industrial Relations Board (CIRB) to take actions deemed necessary to maintain industrial peace during labor disputes.

The union's lawsuit requests that a Federal Court judge annul Hajdu's decision and declare the invoked power unconstitutional and beyond her authority. Additionally, CUPE is seeking an emergency injunction to halt the minister's order.

In the lawsuit, CUPE argues, "In issuing her direction, the Minister overrode, abrogated and effectively precluded the Union’s ability to exercise its legal right to strike and its only legal means of asserting and leveraging economic power within the scheme of the Canada Labour Code." The union contends that Hajdu made legal errors and based her decision on incorrect facts, describing her actions as arbitrary and unreasonable.

As of now, the federal government has not responded to the lawsuit. A spokesperson for Employment and Social Development Canada did not provide immediate comments.

Section 107 has been a point of contention in recent years, as the Liberal government has used it to end various strikes, including those at ports, railways, and Canada Post. On Saturday, shortly after the flight attendants began their strike, which resulted in the cancellation of hundreds of flights, the government invoked this section again, directing the CIRB to order the strikers back to work and to enter binding arbitration.

During a press conference, Minister Hajdu defended the government's actions, stating, "We believe that unions are an essential part of a healthy and growing economy. However, in a case like this, where multiple efforts have been made to conclude an agreement that satisfies both parties and it is clear that they are at an impasse, it is very clear they need some help in arbitrating the final items."

Despite the CIRB's order for flight attendants to return to work on Sunday, CUPE leadership rejected the decision and urged members to continue their strike. The board later declared the strike illegal, but it persisted as the Canadian Labour Congress expressed support for CUPE.

On Tuesday morning, CUPE announced that it had reached a tentative agreement with Air Canada, effectively ending the strike. The lawsuit also claims that after flight attendants voted overwhelmingly for a strike mandate in early August, Air Canada shifted its focus from negotiations to lobbying the government to intervene.

CUPE stated, "On August 12, 2025, Air Canada presented a detailed brief to the Minister requesting that the Minister intervene and pre-emptively order that the Union and its members not be permitted to exercise their legal and constitutional right to strike." The union alleges that Air Canada relied on the expected government intervention, which led to a withdrawal from genuine bargaining efforts.