More than 1,400 flights to, from, or within the US were cancelled on Saturday after airlines were told this week to cut traffic during the federal government shutdown.

Nearly 6,000 flights were also delayed, according to flight tracker FlightAware. The Federal Aviation Administration (FAA) announced earlier in the week that it would be reducing air travel capacity by up to 10% at 40 of the nation's busiest airports due to reports of fatigue from air traffic controllers working without pay during the shutdown.

Both Republicans and Democrats remain divided over how to resolve the impasse, with the shutdown, which began on October 1, continuing into its 39th day, marking the longest in US history.

Senators are negotiating over the weekend aimed at ending the shutdown, which has begun to severely affect many Americans, with cuts to food aid and flight disruptions being particularly pronounced.

In a public statement, American Airlines has urged leaders in Washington, D.C., to reach an immediate resolution to end the shutdown.

Newark Liberty International Airport saw some of the longest wait times, with reported delays averaging four hours for arrivals and 1.5 hours for departures as of Saturday afternoon.

The airports most affected include Charlotte/Douglas International, Newark Liberty International, and Chicago O'Hare International.

The FAA's reductions in flight volumes will escalate gradually from 4% to 10% over the coming days in a bid to maintain safety as air traffic controllers continue to be overworked. Many controllers and other essential workers within the federal government have been working without pay, leading to increased fatigue and staffing issues.

The ongoing disruptions are likely to exacerbate as the busy Thanksgiving travel period approaches, raising concerns among travelers and airlines alike. Restrictions also apply to private jets, which are being rerouted to smaller airports to ease congestion at major hubs.