“Even if you have experience selling on the street, the airport is a whole new world because of the hours of operation,” Mr. Montoya said. “You have to be open 365 days a year. You don’t get your weekends.”

There are also staffing and logistical challenges.

“First it was just me,” he said. “Then I hired a couple people to help, because I had to go buy the inventory and do the payroll.”

Mr. Montoya continued, “But what you have to understand is, the airport is pretty far away from the city, so not that many people want to go out there to work. Then you have to be sure you hire people that can clear security, so background checks become really important. Then once you get them their badge, just getting from the parking lot to your stand can be literally 30 minutes. So you have to have people who can deal with that.”

Francine LeFrak ran into an especially onerous security issue when she set up a kiosk selling handmade jewelry at Newark Liberty International Airport in December. The two employees she hired for the venture — clients of Same Sky, a nonprofit she founded that teaches formerly incarcerated women in Jersey City to become entrepreneurs through jewelry-making — had criminal records.

“One of them was actually wearing an ankle bracelet from the county jail,” Ms. LeFrak said.

The Port Authority of New York and New Jersey has a partnership with a management company to bring small businesses into the airport’s Terminal B. When she brought them her business idea, “I never thought they’d say ‘yes’ to me in the first place,” Ms. LeFrak said.

“Then, once we got in, at every turn there was a headwind,” she said. Mostly, the problem was weather. (The kind that doesn’t cause flight delays.)