What happened

Shareholders of Boeing (NYSE:BA) probably expected a big boost to their stock price on Wednesday, after Reuters reported that the 737 MAX is set for a certification test flight for the Federal Aviation Administration later this month.  

Instead, Boeing stock tumbled 6.2% on the day, taking its parts suppliers Spirit AeroSystems Holdings (NYSE:SPR) and Triumph Group (NYSE:TGI) with it. Spirit was off a Boeing-like 6.9%, and Triumph Group was down 13.6%.

Collage of an airplane, coronaviruses, and a world map.

Image source: Getty Images.

So what

Problems getting the Boeing 737 MAX recertified for flight after a pair of devastating air crashes in 2018 and 2019 caused the airplane to be grounded by airlines around the globe, and began Boeing's stock slide from a high of more than $440 in February 2019, to a low of just $95 in March 2020. Solving this problem might have been cause for celebration among Boeing investors, and the prospect of more Boeing airliners being built would logically mean good things, too, for suppliers like Spirit AeroSystems and Triumph Group.

And yet, some caveats may delay the celebrating just a little while longer. For one thing, the sources Reuters cited, while predicting a certification flight in June, say the date could slip into July. Meanwhile, Reuters predicted that even if everything goes perfectly, the MAX probably won't return to flight before August at the earliest.

Now what

Additionally, today saw a couple of new headlines that bode ill for a resolution of the coronavirus crisis, which has dried up demand for air travel, devastated the airline industry, and cratered demand for new Boeing airplanes.

On Wednesday, Dr. Anthony Fauci, head of the National Institute of Allergy and Infectious Diseases, issued another warning that the COVID-19 pandemic "isn't over yet." And the chief economist for the Organization for Economic Cooperation and Development (OECD), Laurence Boone, noted today that while it's possible that COVID-19 infections will stop after a "single hit" to the global economy, it's just as likely that the world will face a second wave of COVID-19 infections.  

In the latter case, Boone said, GDP in this country can be expected to contract as much as 8.5% in 2020, while next year's GDP might grow only 1.9% -- not the kind of V-shaped recovery that investors have been hoping for. Furthermore, unemployment rates under this scenario could spike as high as 16.9% in the U.S., the OECD said, and remain above 10% through late 2021.  

Numbers like these would not be good for Boeing's business. A 50% chance of a second wave of the coronavirus is a significant risk, and a significant weight on shares of Boeing, Spirit, and Triumph Group.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.