When it comes to major construction projects though, Ms. Cassotis has put the brakes on a $1.1 billion renovation plan given the uncertainty over what air travel might look like once the outbreak starts easing.

It is an issue that many airport officials are likely going to wrestle with.

“Where are the structural changes this industry is going to have to make for people to have restored confidence in it?” Ms. Cassotis said. “How do we help facilitate confidence in travel again? What are the cleaning and social-distancing options for people to want to feel good about traveling again?”

When airline flights into Pittsburgh started dwindling, Ms. Cassotis said she could not consider closing the airport even temporarily because, like Stewart, her airport serves a thriving airfreight sector. FedEx and UPS moved nearly 16,000 metric tons of freight in the first quarter of 2020, slightly less than in 2019.

The military also uses the airport, with the Air Force Reserve 911th Airlift Wing providing coronavirus-relief flights — including carrying medical personnel to New York.

Westchester County Airport did not start out as a commercial facility; it was built for the Air National Guard during World War II. The unit ended up moving to Stewart Airport in 1983. Had it remained in White Plains, it is unlikely that the county could shut down the airport.

Smaller airports play a valuable role in many parts of the country, Mr. Oswald said. They are “how are you receiving high-value, perishable cargo in your community or meeting the air-medical needs. It’s the only access some communities have to the rest of the nation.”