Kai Ryssdal: These are good days for American car markers. Detroit reported March sales today: Chrysler up 34 percent; GM jumped 12 percent. Could be the industry's best month in nearly four years.

More car sales often means more jobs building and selling cars. Thing is, though, there's a bit of a problem with that equation. Marketplace's Adriene Hill explains.

Adriene Hill: Sounds pretty good, right? We want more cars, so auto companies and suppliers create jobs and hire people to make all the widgets and gadgets cars require.

But, there’s a wrinkle.

Christopher Webb: The gap, that had been an employer gap, has now become an applicant gap.

Christopher Webb is with the Engineering Society of Detroit, an organization that holds job fairs. This spring, he says, single companies came in with 600 or 1,000 openings, more than the total number of attendees.

So why the shortage? Especially because it wasn’t that long ago that the industry laid thousands of people off?

Here’s David Cole. He’s chairman emeritus for the Center for Automotive Research.

David Cole: Even for an assembly line job today, it requires a two year community college degree. Where as in the past, that could be a high school dropout.

Combine rapidly changing technology with workers who were pushed into early retirement, and you’ve got too few people who know how to do the jobs the industry is looking to fill.

Neil DeKoker is head of the Original Equipment Suppliers Association, which represents auto parts markers.

Neil DeKoker: I’ve had several of CEOs of small- to medium-size suppliers who are pulling their hair out trying to keep from shutting their customer down.

So they’re working a lot of overtime, doing more on-the job training. But DeKoker says, it’s a problem he’ll take. Far better to struggle to hire than have to lay off people and shut down factories.

I’m Adriene Hill for Marketplace.