Norwegian Air Shuttle ASA has shelved flights between Europe and Canada until next year after delivery delays afflicting Boeing Co. 737 Max narrow-body jets left too little time to market the planned routes.

Services won’t now begin until spring 2019 following a slippage of about four weeks in the handover of two 737s, Norwegian Air Chief Executive Officer Bjorn Kjos said in an interview. Ticket sales had been authorized to start last month with flights due from July 23, according to the Canadian Transportation Agency.

“We got a slight delay, not much, but it gave us a month shorter pre-sale period,” Kjos said at the carrier’s headquarters in Fornebu, near Oslo, adding that the hitch stems from issues with 737 engines made by the CFM International venture of General Electric Co. and France’s Safran SA.

GE aero-engines chief David Joyce said on March 14 that CFM deliveries to Boeing and for Airbus’s rival A320neo were about six weeks behind schedule. That delay has now been reduced to “about a month,” according to CFM spokesman Jamie Jewell. Boeing declined to comment.

Norwegian was also affected by snags with 737 handovers last summer. The carrier currently has six Max planes in its fleet and is due to get another 12 this year, none of which have so far been delivered.

The setback comes as Norwegian seeks to deploy 737s in an unorthodox trans-Atlantic role alongside the larger Boeing 787. The discount carrier already operates the Max on several such routes to smaller U.S. cities, though services between Bergen, Norway, and Providence, Rhode Island, and from Edinburgh to Hartford, Connecticut, are to be discontinued.

Canadian routes would compete with North Atlantic flights at low-cost carriers Air Transat and WestJet Airlines Ltd., as well as Air Canada’s no-frills Rouge arm and numerous full-service operators. Latvia-based Primera Air will also begin services from London, Birmingham and Paris to Toronto this summer using a fleet including extended-range Airbus SE A321neo LR narrow-bodies.

Norwegian Air is set to take delivery of 30 A321neo LRs of its own from 2019 that it says will boost margins and make more routes viable.

Both Boeing and Airbus are grappling with production issues at engine makers and other suppliers as they lift narrow-body production rates to new highs amid record order backlogs. The U.S. company will speed up 737 production to 52 planes a month this year from the current 47.

Norwegian’s first domestic flights in Argentina, with which the carrier aims to establish a bridgehead for wider Latin American services, may now be timed for the start of the high season in October instead of August as initially planned, Kjos said, with a sales system to be established next month.