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.

As many as 1,800 flights could be affected on Friday alone, according to Cirium, an aviation-data provider. The final figure will depend on which airports are targeted. The FAA estimates that it handles an average of more than 44,000 flights a day.

As the longest government shutdown in U.S. history drags on, airlines have been ordered to begin reducing operations on a phased-in basis.

American Airlines said that the 4% reduction will mean 220 canceled flights per day. The vast majority of impacted American Airlines flights are regional, and there’ll be no impact to international flights including Mexico, Canada and the Caribbean, CEO David Seymour said in a letter to employees. Further hub-to-hub routes impact will be minimized.

Airlines are canceling hundreds of flights to comply with the FAA's order. But there are still questions about the plan, which the agency says will keep the skies safe during the government shutdown.

Beginning next week, daytime rocket launches are all officially scrubbed thanks to the government shutdown.

The federal government shutdown, now in its 38th day, prompted the Federal Aviation Administration to issue a temporary emergency order Thursday prohibiting commercial rocket launches from occurring during “peak hours” of air traffic.

At International Airport, things were still running smoothly on the first day of reductions. However, while isn't among the 40 airports directly affected, flights departing from here are heading to destinations that are.

Only two flights have been canceled so far at McGhee Tyson on Nov. 7. Knoxville, so far, has avoided the brunt of the government shutdown impacts on airports. Unlike other Tennessee airports, like Nashville International Airport, long security lines and delays have been minimal.