Flight delays and cancellations are piling up Sunday across the U.S. after the Federal Aviation Administration cut flights at 40 U.S. airports on Friday following a monthlong government shutdown.

Follow live updates as flight reductions begin today at 40 high-traffic airports in what officials have described as a "proactive" effort to alleviate pressure points.

While not all of the canceled flights were caused by the FAA-mandated cuts, airlines have reported cutting hundreds of flights due to the order.

Travelers can expect to see fewer flights to many major U.S. cities starting Friday morning. That's when the Federal Aviation Administration says it will reduce traffic across 40 airports to ease the load on the nation’s air traffic controllers.

Follow live updates on delays, cancellations and FAA impacts as airlines cut flights amid the government shutdown.

The government shutdown hit its 40th day on Sunday as the Senate prepared to reconvene for day two of its rare weekend session to try to move the needle as lawmakers sounded the alarm on rising disruptions to flights and beneficiary programs.

Secretary Sean Duffy said on Sunday that more air traffic reductions are coming if the US government shutdown, which is now on day 40, continues.

Officials say the move is in response to mounting pressure on air traffic controllers who've gone without pay as the shutdown continues.