The Canadian Union of Public Employees says a new agreement reached between WestJet Encore and its flight attendants does not prevent these workers from unionizing.

WestJet Encore announced Tuesday that it has reached peace with its flight attendants by arriving at a "unique" agreement that addresses their key concerns months after the start of a union drive.

The Calgary-based regional service of WestJet Airlines Ltd. (WJA.TO) said the deal effective Jan. 1 covers work rules, compensation, including minimum hours and career progression. The contract will be reviewed annually.

Hugh Pouliot, a spokesman for CUPE, said in an emailed statement that the new agreement "does not prevent CUPE from filing for certification on behalf of WestJet and WestJet Encore flight attendants."

He noted, for example, "that the existence of the WestJet Employee Association did not prevent WestJet and WestJet Encore pilots from unionizing in 2017."

Pouliot added that the agreement is also meaningless when the employer can unilaterally reopen the agreement on a whim. "It has headings similar to a collective agreement but is missing the substance and any viable mechanism for enforcement," he said.

WestJet Encore president Charles Duncan called the agreement simple and fair and said it gives opportunity for more feedback and adjustments.

He said the deal highlights the benefits of employees working directly with the company.

CUPE said in November that it was working to unionize cabin crews at Encore and WestJet.

The Canada Industrial Relations Board certified the Air Line Pilots Association as the bargaining representative for Encore pilots.

That will lead to the group's first negotiations with the airline.