WestJet is beginning to park 737 aircraft across its network as the clock ticks closer to a possible strike by the airline’s flight attendants.

“This necessary step allows the airline to maintain operational control and protect the integrity of the broader network,” WestJet said in an update on its website, adding the measure will help prevent travellers and planes from being stranded.

The company said it was still bargaining with flight attendants in order to try and reach a deal.

WestJet’s flight attendants issued a 72-hour strike notice Thursday, which the airline responded to with a 72-hour lockout notice of their own. That means some 4,287 flight attendants could be off the job as soon as Sunday at 12:01 a.m. MT — over the August long weekend, a busy time for domestic travel.

The airline says WestJet Encore flights and codeshare flights operated by airline partners remain unaffected.

CBC News has reached out to the union, known as the CUPE WestJet Component, for comment. WestJet declined an interview with CBC News, saying its leaders are focused on the negotiations.

In an email obtained by CBC News, WestJet said it had put forward what it believes is the “best agreement we can responsibly deliver” for flight attendants.

That includes an agreement to the union’s request for compensation before and after flights, and a “double-digit” wage rate increase in the first year followed by more wage increases throughout the life of the agreement. 

“The offer would have represented a significant step forward not only for WestJet Cabin Crew, but for the Canadian airline industry as a whole,” the email reads in part.

A key issue at the heart of negotiations has been ground pay. 

Flight attendants say an average of 35 hours per month go unpaid under WestJet’s current “credit hour” system. That pay structure compensates flight attendants for ground duties, delays and other required work by paying them a set amount of credit hours per flight, which can change depending on the trip.

WestJet says the credit system is standard in the industry, and it argues flight attendants are paid at a higher rate under this pay structure in order to compensate for additional duties during what flight attendants consider unpaid time.

More to come.