U.S. air traffic controllers will be offered the opportunity to stay past their mandatory retirement age of 56, U.S. Transportation Secretary Sean Duffy told Fox News on Thursday in the wake of the Washington plane crash.

The new secretary of transportation, Sean Duffy, appeared to walk back an enticement to retire, saying F.A.A. safety workers were exempt from the offer for federal workers.

The strike is in protest of the new Belgian federal government, which plans to make big budget cuts that could lead to public-sector layoffs.

Two U.S. senators called on Wednesday for increased funding and staffing for Federal Aviation Administration air traffic control after a fatal midair collision in the nation's capital last month highlighted the persistent lack of aviation safety personnel.

Air traffic controller staffing has faced renewed attention after a January plane crash in Washington, D.C. Chicago has not been immune from challenges.

Tens of thousands of Belgians took to the streets on Thursday in protest over the new government's planned pension reforms, during the first day of a multi-day strike that halted all air traffic in the country.