After nearly two months, the strike against Boeing is over. Members of the International Association of Machinists and Aerospace Workers voted to accept a new contract Monday night, which means they can get back to work this week.

And there’s no shortage of work to do. The aircraft manufacturer reported a backlog of over 6,000 planes this fall. But it’s not just a Boeing problem. The other big commercial aircraft manufacturer, Airbus, has a similarly large backlog.

Boeing’s turbulent year started with that door plug blowout back in January, after which the federal government limited the company’s capacity to build new planes. 

But there are underlying factors that have made everything a lot harder going back to — surprise! — the pandemic.

“After the pandemic, actually, we observe a huge demand increase in both air freight and passenger side,” said Fecri Karanki, an assistant professor at Purdue University.

As airlines saw more demand to carry people and things post-pandemic, they ordered more planes. The problem was “COVID really did incredible damage to the highly technical aerospace and defense manufacturing supply chain,” said Peter Arment, managing director at RW Baird, which is a Marketplace underwriter.

Hundreds of small companies around the globe supply crucial components to the two big aircraft manufacturers.

And Arment said when pandemic lockdowns hit, a lot of older, skilled workers at those suppliers left and didn’t come back.

“It has affected the productivity side, and it’s just going to take time for that to heal,” Arment said.

But even before the pandemic, a lot of those suppliers were already struggling after Boeing shut down production of its popular 737 Max model following two deadly crashes. 

“When you shut down the ubiquitous airplane, you force your suppliers to either, you know, eat their inventories, or, in some cases, go out of business because they can’t sell them,” said Robert Mann, an independent aviation consultant.

Then, COVID disruptions led to a lot of the remaining suppliers dealing with supply chain issues of their own. 

“So, you’re just jerking the supply chain over and over again and expecting somehow magically for it to recover,” Mann said.

But it hasn’t, Mann said, which has contributed to large backlogs. 

And they are holding back the airlines, said Henry Harteveldt at Atmosphere Research Group.

“Either they’re operating older, more costly, less fuel efficient, planes longer, or they’re not even operating all of those planes, maybe they have to be retired and they shrink,” Hartveldt said.

If they don’t get more new planes soon, Harteveldt said passengers could start to feel it.