Boeing warned that supply constraints in the industry could drag on for more than half a decade, delaying deliveries to airlines and hampering the industry’s rebound from the COVID-19 pandemic.

“I can see supply constraints for a very long time,” Chief Executive Officer Dave Calhoun, appearing on a panel alongside Qatar Airways CEO Akbar Al Baker, said at the Qatar Economic Forum in Doha on Tuesday. “We have backlogs that go out five to six years so if the backlogs would suggest supply constraints that far, that means it’s even further.”

Aircraft manufacturers have struggled to increase production at a time when airlines are clamoring for new jets to meet the surge in demand for travel. Component shortages have restricted output as Boeing and archrival Airbus struggle to scale up production. Calhoun said only after the industry has regained what he called stability – a process that will take about a year and a half – can it really ramp up production rates.

Al Baker said that along with delays of new jet deliveries, supply constraints are also a hurdle for existing fleets, forcing airlines to ground some planes that need spare parts for everything from engines to avionics.

“This is all the consequence of the pandemic,” Al Baker said.

Disclaimer: The government of the State of Qatar is the underwriter of the Qatar Economic Forum, Powered by Bloomberg.