Budget flight company NewLeaf has cancelled more flights in Ontario, B.C., Alberta and Nova Scotia for the next few weeks.

According to a memo sent to passengers, four flights — all on Sundays — have been cancelled, effective Jan. 15:

Hamilton to Halifax.

Halifax to Hamilton.

Abbotsford, B.C., to Edmonton.

Edmonton to Kelowna, B.C.

NewLeaf spokeswoman Julie Rempel told CBC News that the company had to make a "schedule change" for Sundays that will last for six weeks.

"Passengers have either been re-accommodated or can travel with us on a different day," she said.

Flights booked through NewLeaf are operated by Flair Airlines, a licensed Canadian company with pilots flying Boeing 737-400 passenger jets.

Rempel said negotiations with Flair caused the cancellations.

"It's a schedule change due to the fact that Flair needed an aircraft back, so we negotiated a schedule to accommodate with our airline partner Flair," she said.

"It is not a route that is in jeopardy for the long term."

NewLeaf also cancelled flights from Hamilton to Melbourne, Florida as well as Alberta routes to Mesa, Ariz., near Phoenix earlier this month.

Rempel said the company is planning "huge increases" in frequency of service, but did not specify on what routes or when that would be announced.

NewLeaf's first flight took off from Hamilton's John C. Munro airport in July.