Boeing Co. has begun planning for its next all-new airplane, starting with the question of how soon it will shift away from the familiar tube-and-turbofan design that has defined air travel since the dawn of the jet age.

The Chicago-based planemaker is tackling the “prerequisites” for a new plane, according to Stan Deal, Boeing’s chief of commercial airplanes.

That process usually starts with heart-to-heart conversations with key customers about the size, range and fuel savings that might spur them to order the next generation of aircraft. But mapping out the market for jetliners designed to last 30 years is getting more complicated with potentially revolutionary engine technology on the horizon and intensifying sustainability demands.

Boeing’s main rival, Airbus SE, is mulling a family of hydrogen-power aircraft. General Electric Co. and venture partner Safran SA, meanwhile, are working on several futuristic engine technologies in a bid to cut fuel consumption by more than 20% for single-aisle planes.

The dilemma for Boeing is whether to wait to see if the new technology pans out, “or do we run the propulsion system one more time before we go to that next technology suite?” Deal said in a virtual panel discussion hosted by the Royal Aeronautical Society.

Boeing hasn’t shared much about its product strategy as the company works to reverse years of losses from the 737 Max grounding and Covid-19 pandemic. Easing the company’s $58 billion debt load and re-engineering its aircraft-development process to cut down on costly gaffes are high priorities, executives have said.

“We’re not resting and standing still,” Deal said. “We continue to invest.”