Thankfully, no passengers or crew of Alaska Airlines Flight 1282 were critically injured after the frightening blowout of a plug door and piece of fuselage from the 737-9 MAX jet Friday night, which forced the plane to make an emergency landing in Portland, Oregon. Investors in Alaska Air Group (NYSE:ALK) didn’t seem too concerned about the incident either. Shares of Alaska Air were flat in midday trading. But it was another story for Boeing (NYSE:BA) and one of its key suppliers.

Boeing, which makes the 737-9 MAX, tumbled nearly 7%. And Spirit AeroSystems Holdings (NYSE:SPR), the manufacturer of the fuselage that was on the Alaska Airlines plane, plunged over 6%. It’s understandable that traders would be nervous, especially since the Federal Aviation Administration (FAA) quickly announced the grounding of more than 170 Boeing 737-9 MAX planes pending safety inspections. 

Spirit AeroSystems said in a statement that it will work with Boeing on the investigation of Friday’s incident and that it is “following the protocols set by the regulatory authorities.” For its part, Boeing said that “we agree with and fully support the FAA’s decision to require immediate inspections of 737-9 airplanes with the same configuration as the affected airplane.” In addition, a Boeing technical team is supporting the National Transportation Safety Board’s (NTSB) investigation of the matter. And Alaska Air has said it is ready to perform the required inspections of the 737-9 MAX planes in its fleet while the jets remain grounded.

Investors Should Ignore SPR, BA Stocks

So, what does Friday’s incident mean for investors? Even though several analysts were quick to come out with reports defending Boeing Monday morning, the Alaska Air scare is probably another reason for traders to ignore Boeing and Spirit AeroSystems for the foreseeable future.

While airline stocks have started to recover thanks to strong demand for travel as consumers and business people return to the skies, Boeing continues to suffer from a hit to its reputation and concerns about safety following two fatal crashes (one in late 2018 and another in early 2019) of 737 MAX jets that led to the deaths of 346 people.

The 737 MAX was temporarily grounded after those tragedies and Boeing has lost more than $20 billion in the past five years as the company has been forced to delay deliveries of planes while spending heavily to make necessary fixes. (Mounting costs to build new Air Force One planes for the government hasn’t helped either). The production slowdown for Boeing was a big problem for Spirit AeroSystems as well, which has also posted several years of losses because of both the pandemic and Boeing’s delivery woes. Spirit even disclosed in late October that Boeing was spending $100 million to help stabilize Spirit’s supply chain and support production increases.

The Bottom Line

But that development seems like a distant memory now. With safety worries once again surfacing for Boeing and Spirit, both companies are likely to continue to struggle financially. Although Boeing and Spirit AeroSystems are each currently expected to return to profitability in 2024, that’s no longer a certain bet given the new groundings enforced by the FAA. Analysts have already been slashing their profit forecasts for this year for both companies over the past few months due to macroeconomic concerns. That trend is likely to continue given the Alaska Air incident.

Shares of both Boeing and Spirit AeroSystems have tanked for the past five years, missing out on the market’s post-pandemic rebound to near record highs. Boeing has plummeted 35% since January 2019 while Spirit AeroSystems has shed nearly two-thirds of its market value. The Dow Jones, on the other hand, is up more than 50% during the same time frame and the S&P 500 has soared 80%. And with 737-MAX 9 planes remaining on the tarmac for the foreseeable future, it’s hard to imagine a scenario where Boeing and Spirit AeroSystems can gain altitude anytime soon.

As of this writing, Paul R. La Monica did not hold (either directly or indirectly) any positions in the securities mentioned in this article. The opinions expressed in this article are those of the writer, subject to the InvestorPlace.com Publishing Guidelines.