It has been a tough year for Boeing (NYSE:BA) shareholders. The stock lost more than 60% of its value over a three-week period in March on growing COVID-19 fears. Even after showing some signs of recovery, it remains down 45% year to date.

Boeing had concerns prior to the pandemic, with its 737 MAX airplane grounded in March 2019 after a pair of fatal accidents. The 737 MAX issues and an investigation into what went wrong led the company to dump its CEO and has cost Boeing billions in compensation payments to suppliers and customers.

BA Chart

Boeing Year-to-Date Stock Performance, data by YCharts.

It's rare to see a household name industrial stock fall so quickly, making Boeing shares a tempting target for value hunters. But there are real issues the company still needs to grapple with. Here are three things investors should consider before buying into Boeing right now.

The business is stable, but not healthy

Boeing raised $25 billion in fresh debt earlier this year, alleviating investor worries about its viability. The company hopes to have the 737 MAX airborne before year's end, which will allow it to start working through its stockpile of more than 400 assembled but not-yet-delivered jets. That in turn would boost Boeing's cash flow, after it burned through $10 billion in the first half of the year.

Unfortunately, this is likely to be a multiyear process. And Boeing needs to balance working down inventory with preserving the health of its supply chain. Prior to the 737 MAX issues, Boeing had hoped to be manufacturing more than 55 MAX jets per month by now. Instead, Boeing will make fewer than 80 in all of 2020 and hopes to gradually rebuild production to 31 planes per month by 2022.

Boeing is also scaling back production of other models that last year generated much-needed cash and helped keep the company out of crisis mode. The company delayed introduction of its 777X until 2022, announced plans to discontinue the 747, and is scaling back production on the 787 and 737 MAX. Those are the types of decisions made if you expect the slowdown to last years, not just quarters.

Boeing's 787 Dreamliner in flight.

Image source: Boeing.

Prepare for a long downturn

Commercial aerospace was on a good run entering 2020, in year 16 of an up cycle without a major downturn. That's much longer than normal for this typically boom/bust business. Even prior to COVID-19, there were reasons to worry demand was beginning to slow, especially for larger planes like Boeing's 777 and 787 Dreamliner.

Post-pandemic, it will be increasingly hard to move metal. U.S. airlines alone have taken on more than $50 billion in added debt to survive COVID-19 and will need years to resuscitate badly-bruised balance sheets. With airlines expecting traffic to remain well below pre-pandemic levels until at least 2022, it could be the second half of the decade before we see real growth in fleet sizes.

There will be some demand for replacement aircraft, but as long as oil prices remain stable and relatively low, there isn't a pressing need to replace older, paid-for planes. Boeing had been counting on emerging markets to drive future demand, but due to the global nature of the pandemic, the entire world market has been impacted. Throw in added risk from growing tensions between the U.S. and China, and Boeing's sales team has a real challenge ahead.

Defense won't save the day

Boeing, unlike many of its suppliers, has a large defense business to fall back on during a commercial downturn. For the last decade, the defense business has played second fiddle at Boeing. It has also been the target of criticism from government officials in years past.

But Boeing's defense business has been on a roll for the past two years, winning a number of key contracts. It is also in the running for a $12 billion award to supply new fighter jets to Canada, among other large prizes.

Boeing-made F-15s in flight.

Image source: Boeing.

Alas, most of those new awards are in their early years and aren't mature enough to be major profit drivers to offset pandemic-related woes. It also seems likely that after years of growth, the Pentagon budget will soon slow, in part due to government pandemic relief spending.

Defense is an important part of the long-term bull case for Boeing. But this company has lived and died by its commercial business for the past decade-plus, and there is no reason to expect that to change in the years to come.

Is Boeing a buy?

Absent some fresh issue with the 737 MAX, Boeing shares are unlikely to retest the lows they hit back in March. The company has a solid aerospace portfolio that will outlast the pandemic and whatever economic downturn that follows. Once airlines eventually get airborne, it will thrive again.

That said, it is hard to see a catalyst that would cause Boeing shares to rapidly gain altitude any time soon. And there are still risks involved in the 737 MAX recertification process and unknowns about airline and passenger preferences once the plane is flying again. Boeing has only taken half-steps to rework cultural issues exposed by the MAX debacle and has a product lineup that arguably doesn't match up well with near-term demand.

I'm a long-term believer in aerospace and a rebound in air traffic, but I see far better investments than Boeing to take advantage of those trends. There isn't a good reason to buy Boeing today.

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.