The airline industry is facing a shortage that is as fundamental as it gets for any business sector. The Wall Street Journal reports that aircraft manufacturers Boeing and Airbus are months behind in handing over new single-aisle jets, as persistent supply-chain problems and regulatory concerns rattle the business from assembly plants to tarmacs.

The shortfall is affecting planning at carriers including American Airlines and United Airlines. Boeing says it is working with suppliers to keep parts moving, but the plane maker also faces regulatory challenges over the 737 MAX.

Airbus appears to be about as far behind in deliveries this year, says data provider Ascend by Cirium, and the company expects to face supply constraints into next year. 

In some cases, Boeing is planning to remove engines from planes stored during the pandemic and use them for new jets rolling out of its Renton, Washington, plant.