The country's second-largest carrier, which operated 13 MAX jets, said in a blog post it would reduce frequencies, and suspend certain domestic and international routes like Halifax to Paris for the rest of the summer season. The carrier had previously taken the 737 MAX out of its schedule until August.

The 737 MAX was grounded worldwide in March after an Ethiopian Airlines plane plunged to the ground soon after take-off, five months after a similar Lion Air fatal crash off the coast of Indonesia.

Boeing Chief Executive Dennis Muilenburg told analysts last week he was confident the MAX would be back in service as early as October after a certification flight with regulators in September.

North American airlines have canceled thousands of flights because of the grounding, with Southwest Airlines Co last week extending its MAX-related cancellations until Jan. 5, 2020, and announcing it would end operations at Newark Liberty International airport.

Since the March grounding, WestJet said it was able to maintain "98 per cent of our total planned departures, meaning of approximately 175,000 flights, we canceled only 3,661."

WestJet, which is being taken private by buyout firm Onex Corp, last week reported a surprise quarterly profit and better-than-expected revenue despite the grounding.

The country's largest carrier Air Canada has taken the plane out of its schedule until Sept. 2.

(Reporting by Allison Lampert; Editing by Tom Brown)