Boeing Co. is still dithering over whether to update its top-selling 737 single-aisle jet with new engines or introduce a whole new model for the next decade, but a company executive said on Monday it aims to come to a firm decision around the middle of this year.

Boeing has signaled that it is considering building a new single-aisle plane for introduction in the 2019-2020 time range, but still hasn’t made a definite decision on how it will counter rival Airbus’ decision to put new engines on its competing A320 family of aircraft.

Boeing “aims” to come to a final decision on the issue by mid-year, Randy Tinseth, vice president of marketing for Boeing’s commercial airplanes unit, said at a briefing for reporters at the planemaker’s Everett, Washington, facility north of Seattle.