About 3,000 of WestJet's cabin crew members are now officially unionized after the Canada Industrial Relations Board issued an interim order naming the Canadian Union of Public Employees (CUPE) as the certified bargaining unit for employees.

According to a statement from WestJet, the order came in mid-afternoon Tuesday.

A mass email sent by CUPE to flight attendants read: 'Congratulations, we did it!!!'

The message went on to say, "This is an amazing step forward for WestJetters.

"We knew that we could do it together. Now we begin the work of building our local and preparing to bargain our first collective agreement."

A statement provided to CBC News by WestJet said that the interim order will let the company make submissions by Aug. 10 about what positions they want excluded from the scope of the newly formed bargaining unit.

"We are disappointed by this outcome but respect the rights of our employees to choose their representation," Ed Sims, WestJet president and CEO, said in a prepared statement Tuesday. "We now shift our focus to working effectively with CUPE in the interest of success for WestJet as a whole."

CUPE says the interim order is based on forthcoming negotiations needed with the company to determine who is included and excluded as union members.

The interim order is specific to WestJet employees only and does not include cabin crew working for Encore or Swoop.

"We know that Swoop flight attendants want and deserve a union and we will work with them to bring them into the family, along with Encore, in the near future," CUPE said.

Earlier on Tuesday, WestJet posted rare losses of $20.8 million in the second quarter, attributed to a labour dispute with pilots, higher fuel prices and increased competition.