In a forecast released last month, Airbus says future global passenger airplane needs will more than double in the next 20 years.

The airplane maker’s Global Market Forecast 2018–2037 projects 37,390 passenger and freighter aircraft will need to be built to meet demand — carrying a price tag of $5.8 trillion. Many of those planes (26,500) will be needed to meet growth, while 10,850 will replace existing planes.

The company estimates three quarters of the requirement (28,550 planes) will be required in the “Small” segment, which typically refers to single-aisle planes.

Airbus’s largest plane, the A380 superjumbo, lagged in sales in recent years. Airbus says the demand for planes in the Extra-Large segment, including the A380, are around 1,600 planes.

Airbus says passenger traffic is growing at “a resilient 4.4 percent per year,” thanks to factors like higher disposable incomes and “a near doubling of the middle classes globally.” Emerging economies are projected to account for more than 60 percent of the growth.

“There is a growing trend to use aircraft across a broader range of operations, with today’s more capable aircraft blurring the boundaries between market segments. These realities made us develop a new segmentation with Small, Medium, Large and Extra-Large categories, reflecting more closely the way airlines operate aircraft,” said Eric Schulz, chief commercial officer, Airbus.

“Thanks to the versatility of our leading, most comprehensive family of aircraft, the top end of our single aisles, the A321neo, fly efficiently on long haul routes and our wide bodies like the A330neo equally serve regional operations. We’re extremely strong in this Medium market segment.”