(NewsNation) — A NOTAM computer system failure at the Federal Aviation Administration caused a temporary nationwide pause in flight operations Wednesday morning.

As of 9:30 AM CT, 13,450 flights had been delayed and 2,316 had been canceled, according to FlightAware.

The FAA later announced that normal air traffic operations started resuming gradually at all U.S. airports later in the morning, but it still caused a lot of disruption nationwide.

According to the Federal Aviation Administration, NOTAM stands for Notice to Air Missions.

Originally, the acronym was for “Notice to Airmen,” but this was later changed to be “inclusive of all aviators and missions.”

It is, according to the FAA’s website, a memo containing information about abnormal conditions that is important to flight operations employees like pilots. This information isn’t known far enough in advance to be publicized by other means, the FAA said.

Information conveyed on a NOTAM can be as basic as airport weather or active taxiways, or as complicated as temporary airspace closures because of a space launch or presidential travel.

Warnings can include information about runway conditions, weather, airport construction or the presence of hazards — including drone, military or parachute activity — near an airplane’s flight path.

NewsNation correspondent Markie Martin, who is a licensed pilot, says NOTAMs are “crucial.”

“These are potential hazards and extremely necessary to be aware of,” she said. “Maybe the airport you’re landing at has a closed runway, so you’ve got to use another one, maybe the entire airport itself is closed, maybe it’s an obstacle that you need to know about (for) safe landings or takeoff.”

There are two primers the FAA uses for airports and pilots that identify common issues and best practices for using NOTAMs.

The New York Times reports that NOTAMs were created in 1947 and modeled after messages used to alert captains to hazards at sea.

Travel expert Peter Greenberg said on “Morning in America” that currently, NOTAM is an antiquated system, but the FAA is trying to change that. NextGen, also known as the Next Generation Air Transportation System, is a multibillion-dollar infrastructure program the FAA is working on to modernize the U.S. National Airspace System.

“The irony about it is that the FAA has been talking about NextGen for two generations,” Greenberg said. “This will be a huge wake-up call to get Congress to act to perhaps possibly give them more money to get it in place sooner.”

At a little after 6:30 a.m. Wednesday on Twitter, White House press secretary Karine Jean-Pierre said President Joe Biden was briefed by Secretary of Transportation Pete Buttigieg on the FAA system outage.

While she said there was no evidence of a cyberattack, the president directed the Department of Transportation to conduct a full investigation into the causes.

“The FAA will provide regular updates,” Jean-Pierre said.