WASHINGTON ― The U.S. aerospace and defense sector is feeling the impact of the coronavirus, with companies limiting travel, defense trade events scuttled and contingency planning underway.

As stocks fell sharply Monday on a combination of coronavirus fears and plunging oil prices, defense firms were girding for the worst and looking to the White House for guidance. The comments came days after spread of the coronavirus forced the weeklong closure of two F-35 related facilities in Italy and Japan―a sign the outbreak had begun to impact operations within the American defense industrial base.

“The normal ways of doing business are definitely going to change,” said Aerospace Industries Association CEO Eric Fanning. “We’re trying to get to the place where we’re not reacting on a day-to-day basis to what’s happening and getting in front of some of these things and maybe making some proactive decisions. But everyone is kind of looking to everyone else to take the lead on how to address this.”

Lockheed, Raytheon and Honeywell were among dozens of companies that pulled out of last month’s Singapore Air Show, which is typically the largest defense trade show in Asia―and SXSW, a show AIA participates in, was cancelled. The two offer a glimpse into how fears of corona virus could impact other defense trade shows and conferences.

“It felt like a ghost town. It definitely was a strange experience,” Fanning said about the Singapore conference.

While it’s easy to overstate the importance of trade shows in cementing major deals, the deals announced at the shows are often worked out in advance, Fanning said. Still, the shows are still valuable for face-to-face networking between international defense officials and industry.

As of Monday, the National Defense Industrial Association still planned to hold its Special Operations Forces Industry Conference in Tampa, Fla., this May. Its 2020 Pacific Operational Science and Technology Conference in Honolulu was ongoing this week, with more than 700 attendees, a spokeswoman said.

At least one major defense firm, Boeing, has limited its employees to “business-essential” travel, and it has been rescheduling some events, reducing face-to-face meetings in favor of virtual meetings, enabling telecommuting when possible.

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“These measures are temporary and aimed to prevent the spread of the virus, shorten its impact and ensure the health and safety of our employees as well as the general public," a Boeing spokesman said.

Vice President Mike Pence, right, along with Florida Sen. Rick Scott, left, and Gov. Ron DeSantis, center, speaks to the media after a meeting with cruise line company leaders to discuss the efforts to fight the spread of the COVID-19 coronavirus, at Port Everglades, Saturday in Fort Lauderdale, Fla. (Gaston De Cardenas/AP)

The virus has infected more than 110,000 people worldwide, and Italy on Sunday followed China’s lead in quarantining a big swath of its country in hopes of corralling the spread. That sparked more fears in the financial markets that quarantines would snarl supply chains for companies even more than they already have.

While COVID-19’s long term impacts on the defense aerospace industry may take time to manifest, they could be complicated by the uncertainty of the financial market and ongoing trade wars with China, according to Fanning and others.

“Supply chains are global, they’re inter-related, they’re incredibly complex. Having real good situational awareness into them is difficult to begin with, then you add any instability on top of it, it gets harder. And this definitely is added to that,” Fanning said.

The new coronavirus is now spreading on every continent except Antarctica and hurting consumer spending, industrial production, and travel.

As COVID-19 spreads around the world, many investors feel helpless in trying to estimate how much it will hurt the economy and corporate profits, and the easiest response to such uncertainty may be to get out. After initially taking an optimistic view on the virus — hoping that it would remain mostly in China and cause just a short-term disruption — investors are realizing they likely woefully underestimated it.

On Monday, the Dow Jones U.S. Aerospace & Defense Index was down 26 percent over the last month, lagging the Dow Jones Industrial Average, which was down 18 percent.

“Defense should do relatively better [than consumer sectors], but it’s not gonna be immune,” said Byron Callan, a policy research expert at Capital Alpha Partners. “It’s gonna catch a mild fever where, you know, there are gonna be other parts of the U.S. economy that are gonna be in a critical situation."

“Buy-America” regulations and other controls mean the U.S. defense industry’s supply chains may be less susceptible to disruption than some consumer sectors, where reliance on China-made components is more widespread―and few, if any supply chains are as globally linked as the F-35’s, said U.S. Chamber of Commerce’s Defense and Aerospace Export Council’s president, Keith Webster.

“I would say in the U.S. defense sector’s supply chain is less vulnerable than maybe a product in the commercial sector, but we’ll have to see,” Webster said. “If this continues across the F-35 partner nations, with their industrial sharing, one could see an impact.”

On the flip side, China’s weeks-long factory closures could eventually see parallels in the U.S., if the virus is not quickly contained. White collar employees may be able to telecommute, but if skilled laborers are forced to stay home, that could mean problems for the primes and their lower-tier suppliers.

“Are there parallels to China in the U.S.? We don't know,” Webster said. “The first step is containment, and the next step is mitigation. China went into mitigation very quickly, which is keeping everybody home. We’re just beginning to see that thought process here.”

Short of factory closings, factory workers staying home for school closures or to care for sick relatives could trigger work slow downs, particularly at the lower tiers of the supply chain, especially the ones that rely on smaller pools of workers. Those companies could suffer too if they rely on the commercial side of the aerospace sector, which is expected to be harder hit, Callan said.

“You can see the ramifications on the pace of work, but it’s not like the airline industry or the cruise ship industry where all of a sudden none of your customers show up,” Callan said, adding: “There could be a cascading effect from some commercial aerospace. Again, it’s at very, very small level, but it’s still a factor.”