On Friday morning, U.S. airlines delayed flights along the East Coast as the Federal Aviation Administration dealt with staff shortages at two air traffic control facilities where more workers than usual called in sick.

By afternoon, the federal government, which was shut down for more than a month — and two employee pay periods — was set to reopen after President Trump accepted a deal that did not meet his initial demands. It’s a short-term solution, with the government funded for three weeks. But considering the Trump Administration had dropped hints the government could remain closed into March, this is a major development.

Is it a coincidence the government reopened on the same day some of the nation’s air travelers suffered a major inconvenience? And on the same week the entire aviation system — from airlines to controllers to TSA screeners — raised the stakes in their campaign to force the government to reopen?

Probably not.

Roughly 800,000 government employees were furloughed or working without pay during the 34-day shutdown, including FBI and Secret Service agents. National parks weren’t maintained, and for awhile the Food and Drug Administration wasn’t inspecting food. The Internal Revenue Service was open, but about 14,000 agency employees weren’t showing up, the Washington Post reported.

Yet more than anything else, aviation seemed to attract the publics’s (and the president’s) attention. About 48,000 Transportation Security Administration employees and 15,000 air traffic controllers hadn’t been paid for more than a month, and in recent weeks, many were expressing their frustration in a way that affected travelers.

On Sunday, more than 10 percent of TSA screeners called in sick, leading to longer than usual lines on a holiday weekend. For the most part, controllers were still working, but that began to change Friday, when some unexpectedly called in sick. Their union issued a statement saying it didn’t condone the job action, but adding: “Many controllers have reached the breaking point of exhaustion, stress, and worry caused by this shutdown.”

The union warned of more problems. “Each hour that goes by that the shutdown continues makes the situation worse,” it said.

What’s interesting is that, while some travelers reported problems, the air travel situation hadn’t yet become a disaster.

During the worst of Friday’s delays, American Airlines, with hubs in Philadelphia, Charlotte, and New York, said it hadn’t experienced “significant” operational issues. And while TSA screening was taking longer than usual at some airports, only a few — Boston and Atlanta among them — were reporting extra-long wait times. On Thursday, the agency reported 95.4 percent of passengers waited less than 15 minutes, even though 7.6 percent of employees didn’t show.

But pressure was mounting. Airline executives were making stronger statements, begging the government to reopen. Union leaders also were issuing shaper criticism, and business interests said they feared economic output would lag if travelers began to avoid air travel.

Flyers, who can be nervous about air travel under the best of circumstances, were asking whether they should postpone future trips. They asked if the system was safe (it was), and wondered whether they would face extra-long lines at airports. (They might, depending on the airport and their travel day.)

Friday morning’s East Coast delays only added to the fears.

“This morning’s reports of air traffic control delays are the strongest indication yet that the shutdown runs the risk of sending immediate shockwaves throughout the American economy,” said Jonathan Grella of the U.S. Travel Association.

U.S Travel estimated the shutdown may have cost the nation’s travel economy as $100 million per day. And aviation generates about 7 percent of U.S. GDP, Alaska Airlines CEO Brad Tilden said Friday in a blog post. Tilden implored the government to reopen, saying, “We expect the shutdown will become much more disruptive to the aviation system if it continues much longer.”

Tilden was one of several U.S. airline CEOs to take a sharper stance this week. Last week, United Airlines and Delta Air Lines reported fourth quarter earnings, and while they said the shutdown was affecting business — Delta said it was losing $25 million in revenue per month, mainly from reduced government-funded travel — they were generally muted in their criticism of political leaders.

On Thursday, though, four more airlines reported earnings, and they were harsher.

“I’ll sum it up in a word — maddening,” Southwest Airlines CEO Gary Kelly said. “Everyone needs to be on notice and on guard that this shutdown could harm the economy and it could harm air travel.”

JetBlue CEO Robin Hayes , who said the system was close to a “tipping point,” warned the airline was expecting significant flight delays and cancellations and said passengers likely would wait in longer security lines as it continued. JetBlue executives noted they already had seen a “modest” affect on passenger demand for air travel because of the shutdown.

“We are increasingly concerned about the shutdown’s consequences for convenient and efficient air travel and for the economy overall,” Hayes said. “The longer this goes on, the longer it will take for the air travel infrastructure to rebound.”

This could all happen again in three weeks. But lawmakers and the president have seen what happens to the nation’s aviation system when they shut down government, so maybe they’ll work harder on a long-term deal.

Photo Credit: Travelers waited in line for security screening last month in Washington, D.C. In recent weeks, fewer screeners have been showing up to work. Zach Gibson / Bloomberg