WestJet has postponed its planned integration of Sunwing Airlines, a move that represents a setback for the Calgary-based company after acquiring the leisure carrier last year.

In an email, WestJet said it will weave the discount airline's fleet into its own by late April, six months after the integration date initially set for Oct. 26 of this year.

Both airlines will continue with "business as usual" on their winter flight schedules, said spokeswoman Madison Kruger.

The longer timeline comes as pilot shortages continue to plague the industry. 

The delay is due in part to pilot training, said Rick Jones, WestJet's interim head of route planning, at a conference in Washington, D.C., on Monday.

But union turbulence may also play a role.

"With safety, people and guests at the forefront, the WestJet Group intends to integrate as much of Sunwing Airlines as possible by its original October 2024 date. The WestJet Group expects unionized operational team members will be integrated in a phased approach to meet training and aircraft transition schedules by April 27, 2025," Kruger said.

Wrangling over worker seniority for pilots slated to fly under the same banner remains a point of contention, said John Gradek, who teaches aviation management at McGill University

"There is a union issue there," he said.

The two sets of pilots are represented by different labour groups — the Air Line Pilots Association at WestJet and Unifor at Sunwing.

"You've got a 20-year captain on Sunwing who's going to be integrated into WestJet. Does he have the equivalent of a 20-year captain at WestJet, or is he going to the bottom of the pile?" Gradek asked.

"This is the same thing that Air Canada went through when they got Canadian Airlines 25 years ago."

Neither union replied immediately to requests for comment.

WestJet acquired Sunwing's main airline and vacation divisions last May in a major consolidation of the Canadian aviation market. Sunwing Vacations will continue as a separate brand.

Meanwhile, WestJet faces more indefinite delays on dozens of pending Boeing aircraft deliveries after a door plug blowout on a 737 Max plane flown by Alaska Airlines in January that prompted a halt to production expansion at the U.S. aircraft maker.

WestJet has signed multibillion-dollar deals with Boeing for at least 65 planes — 50 of them 737 Max 10s — by 2029 in a move the carrier has called a "game-changer" that would reduce fuel costs and "underpin" its growth.

However, the Max 10 has yet to receive final certification and, after the panel blowout, U.S. regulators said they would halt production expansion at Boeing until a full investigation was complete — a process that could take over a year.

Asked whether compensation was on the table for WestJet, Boeing Global president Brendan Nelson said that "in this particular case, there are conversations we have with our customers directly."

"We're working with every single customer to do our utmost to see that we can support their needs when they need the aircraft," he said during an interview in Montreal on Tuesday.

Some experts say Boeing may have to provide effective discounts to airlines such as WestJet that are earning less because of the older, less efficient planes they're stuck with in the absence of new deliveries.

"'Instead of paying $250 million for a 787-9, we want that to be $150 million,'" said John Gradek, a lecturer at McGill University's aviation management program.

"In essence, Boeing is going to have a much less profitable future as a result of carriers asking for significant discounts on airplanes that are already on the order books."

Last month, United Airlines said a deal with Boeing would provide the carrier with "credit memos" for future purchases to compensate for financial damages done by a three-week grounding of its 737 Max 9s and rescheduled deliveries.

Credit memos are written acknowledgements that the buyer is owed money back.

This report by The Canadian Press was first published May 21, 2024.