The 35-day partial government shutdown could spur early retirements among the already thin ranks of air-traffic controllers and may postpone adoption of critical satellite-based aircraft navigation, a union official warned.

It will take years to recover from the disruptions that resulted from people being kept off the job while safety-critical employees like controllers had to work without pay, Paul Rinaldi, president of the National Air Traffic Controllers Association, said in a speech on Tuesday in Washington.

"This shutdown cut us deep," Rinaldi said. "It cut government employees deep. It cut our aviation industry deep. We're just starting to stitch it back up. We're not even sure what the damage really is."

Air-traffic staffing is at a 30-year low and more and more retirements could cause periodic slowdowns in the aviation system, Rinaldi said. In recent days, he added, he's heard reports of at least a handful of people opting to leave earlier than anticipated as a result of the shutdown.

"We know we have lost some," he said.

Computer Upgrade

The shutdown also halted work on a computer upgrade needed so controllers can track planes using so-called ADS-B instead of radar. The upgrade is an important foundation of the modernization effort known as NextGen that's designed to make flight paths more efficient and safer. Airlines and other aircraft operators are spending billions of dollars to equip their planes with the satellite technology before the end of the year.

The Federal Aviation Administration has said it's setting priorities after the shutdown as it attempts to resume normal operations. "We will do our best to keep ADS-B on track and on schedule," the agency said in a statement after Rinaldi's speech.

The nation's controllers, who were forced to work without pay for 35 days during the funding impasse, seemed to be a catalyst to bringing the standoff to an end on Friday. When six controllers out of 13 called in sick at a Virginia air-traffic facility, the agency couldn't handle the normal flight volume along the East Coast and began holding planes on the ground.

The flight delays that cascaded to New York's LaGuardia Airport and other airports were never officially linked to the shutdown and, according to the union, overall controller absentee rates had been lower than average. But the delays nevertheless became emblematic of the growing dysfunction in government and prompted widespread news coverage.

By Friday afternoon, a temporary impasse had been reached allowing lawmakers and President Donald Trump until Feb. 15 to reach agreement on government funding.

Starting Dec. 22, funds had been halted for more than a dozen major agencies and departments in a dispute over Trump's demand that Congress approve $5.7 billion for a wall on the Mexico border. Democratic lawmakers objected to the wall.

Rinaldi said he had begun hearing reports of his members making errors during the shutdown as a result of the stress from working without pay. While the errors didn't directly jeopardize safety, it was a sign that things were getting worse.

As a result of the shutdown, the FAA halted training for new controllers, postponed work on multiple new technology systems and stopped monitoring routine safety reports, Rinaldi said.

While the FAA hopes to resume training new controllers at its academy in Oklahoma City, it was closed for weeks and the contract employees who help with training may never get the back pay that Congress has already guaranteed for federal employees, he said.

One of the frustrating aspects of the shutdown is that the FAA's Airport and Airway Trust Fund, which is funded by taxes and fees mainly paid by aircraft flying in the air-traffic system, couldn't be used to pay for normal government operations, Rinaldi said. It has a surplus of more than $6 billion and should be used to ensure that future shutdowns don't hit the air-traffic system, he said.