The US Federal Government shutdown has begun to impact the US aviation, with air traffic control towers closing and flight delays mounting due to staffing shortages, reports the Associated Press.

Hollywood Burbank Airport's control tower shut down for nearly six hours, forcing pilots to self-coordinate. Delays averaged two-and-a-half hours, marking one of the first visible effects of the shutdown that began on October 1.

The Federal Aviation Administration has reported controller shortages in cities including Boston, Philadelphia, Atlanta and Houston. Delays have spread to Nashville, Dallas and Newark.

The Transportation Security Administration has also seen a rise in unscheduled absences. While major disruptions have not yet occurred, union officials warn longer security lines may follow as workers miss paychecks.

Experts say the shutdown exposes long-standing vulnerabilities in the aviation system, including chronic understaffing and outdated equipment. The FAA had just begun hiring 2,000 new controllers and planning a US$12.5 billion technology overhaul.

Nick Daniels of the National Air Traffic Controllers Association said staffing is at a "critical" low, with even minor absences causing disruptions. He added that controllers are working with unreliable equipment.

The shutdown may worsen staffing gaps, with union leaders warning that newer controllers and TSA trainees could abandon the profession. TSA officials also fear more screeners may quit amid uncertainty.

The 2019 shutdown lasted 35 days and led to lawsuits, sick-outs and terminal closures. Lawmakers and industry leaders then called for reforms to keep FAA funding uninterrupted during future shutdowns.

Despite those warnings, aviation attorney Ricardo Martinez-Cid said the system remains vulnerable. "We're long overdue for a wake-up call," he said.