Thousands of US flights were grounded Friday morning as a technical disaster impacted businesses worldwide – leading to cancellations, delays and confusion at airports across the country.

A cybersecurity company said the debacle is “not a security incident or cyberattack.” But the technical fiasco has paralyzed airlines, banks, state agencies and even emergency services around the world.

As of Friday morning, more than 2,000 flights into, out of or within the United States had been canceled, according to FlightAware.com. Charlotte Douglas International Airport in North Carolina told passengers to not come to the airport unless they had confirmed their flights. Bewildered travelers at the world’s busiest airport in Atlanta were stranded as they tried to get to urgent events.

“So tomorrow, I have a funeral in the afternoon. And then on Sunday, I have my sister’s 50th birthday party,” said Ty Kelley, who was stuck at Hartsfield-Jackson Atlanta International Airport – which had the most cancellations Friday morning.

“It’s really chaotic. It’s frustrating. And I’ve never experienced anything like this before at this airport.”

Live updates: Global tech outages hit airlines, banks and businesses

The Federal Aviation Administration “is closely monitoring a technical issue impacting IT systems at U.S. airlines,” the agency posted on social media. “Several airlines have requested FAA assistance with ground stops until the issue is resolved.”

CrowdStrike, a cybersecurity firm that has Microsoft among its clients, “is actively working with customers impacted by a defect found in a single content update for Windows hosts,” CEO George Kurtz posted on X. “This is not a security incident or cyberattack.”

Kurtz later told NBC, “We’re resolving and have resolved the issue.”

“As systems come back online, as they’re rebooted, they’re coming up and they’re working,” Kurtz said on the “Today” show. However, Kurtz said, it could be “some time” for certain systems that won’t just automatically recover.

What US airlines are saying

– Delta Air Lines “paused its global flight schedule this morning due to a vendor technology issue that is impacting several airlines and businesses around the world,” it said in a statement Friday morning. Delta later said it was resuming some flights. The airline apologized to impacted customers and said a travel waiver would be issued.

– JetBlue’s operations “remain normal and we are not experiencing any system-wide delays or cancelations,” the airline said in an email to CNN. However, “Customers should monitor their flight status and build in extra time in the event that this outage has impacted specific airports due to outages at other airlines, airport operators, or government agencies.”

– American Airlines said it has resolved the issue affecting its operations. “Earlier this morning, a technical issue with a vendor impacted multiple carriers, including American. As of 5 a.m. ET, we have been able to safely re-establish our operation,” American said in a statement. “We apologize to our customers for the inconvenience.”

– Spirit Airlines said in a travel advisory its reservation system was impacted by the outage. The airline asked passengers to check back for updates and apologized “for any inconvenience this may cause.”

– Southwest Airlines told CNN the outage hasn’t impacted its operations.

– Frontier Airlines and some competitors were brought to a standstill for hours after a significant Microsoft outage Thursday. The ground stop for those airlines has been lifted, and Frontier offered refunds to inconvenienced passengers.

– United Airlines said it was resuming “some flights” early Friday morning. United cautioned travelers they might experience delays and issued waivers for eligible customers to change their travel plans.

– Allegiant Air and Sun Country Airlines said they were having difficulties involving booking, check-in and trip-managing functions online. The FAA announced Friday morning that all Allegiant flights would be grounded.

– Numerous international airlines reported technical disruptions, including Virgin Australia and Qantas, along with airports across Europe and Asia-Pacific.

Some 911 services weren’t working

In addition to flights, the technical disaster has affected some 911 operations in the United States; mass transit in New York and Washington, DC; banking in Australia, South Africa and the United Kingdom; Hong Kong’s Disneyland; and the Israeli health service.

In Alaska, many 911 and non-emergency call centers aren’t working properly across the state, state troopers said in a Facebook post.

In New Hampshire, some 911 services were down across the state overnight but have since been restored, New Hampshire 911 said in a post.

Phoenix police said the technical problems impacted the department’s computerized 911 dispatch center. “Our 911 center remains operational. If you need to call 911, stay on the line if you are put on a brief hold,” Phoenix police posted on X Friday morning. Later in the morning, the department said its “systems have been restored.”

In New York City, 911 services are operational, the mayor’s press secretary told CNN.

“FDNY IT and Communication teams implemented our redundancy procedures upon notification of the CrowdStrike outage,” New York fire department spokesperson Jim Long told CNN Friday.

CNN has reached out to the Federal Communications Commission for more information on nationwide 911 outages.

“We’re aware of reports of a systems outage causing disruptions in service, including 911,” the FCC posted late Friday morning on X. “We’re working closely with other federal agencies to provide assistance and determine the extent of these service disruptions.”

State agencies are hit hard, too

In some states, driver services grinded to a halt due to the technical problems.

North Carolina’s driver’s license and plate services are “unable to assist customers this morning due to the current global Microsoft and CrowdStrike outage,” the North Carolina Department of Transportation said. The agency said services will resume “once the global outage has been repaired.”

Georgia’s Department of Driver Services said operations were unavailable “Due to the Microsoft/CrowdStrike Global outage.”

And in Tennessee, driver services centers might not be able to process transactions, state officials said Friday morning.

“The Department of Safety and Homeland Security will provide updates as information becomes available,” the agency said. “We apologize for the inconvenience the outage has caused.”

Some airports are ‘absolutely insane’

The situation at Philadelphia International Airport is “absolutely insane” as thousands of people cram together, waiting for answers, traveler William Sikora III said.

 “It’s getting really hot in here,” Sikora told CNN on Friday morning. He was trying to make the cross-country journey from Philadelphia to Los Angeles, but feared repeated delays would eventually turn into cancellations.

His sentiments were echoed by would-be passengers in Atlanta, where airport officials told CNN they expected 300,000 passengers to pass through the world’s busiest airport.

“Nobody was really giving us answers. They just said our system’s down, our system’s down,” New Jersey resident Jennifer Small told CNN.

She slept at the airport overnight and has had her flight canceled twice. “I want to get home to my son,” Small said. But she doesn’t think she’ll be able to go home until Saturday.

Spirit Airlines customer Miya Haney was stuck in Atlanta with her toddler daughter, trying to get to Boston for a birthday party.

“I’m just beyond frustrated,” Haney said. Spirit Airlines was using a manual check-in process, with “a person going up and down shouting ‘Boston here, flight number here,’” Haney said.

“I have no idea when we are going to get called.”

This is a developing story and will be updated.

CNN’s Kaila Nichols, Rebekah Riess, Amanda Musa, Kristina Sgueglia, Whitney Wild, Hannah Rabinowitz, Isabel Rosales, Jaide Timm-Garcia, Shawn Nottingham, Keith Allen, Samantha Waldenberg, Robert North and Dianne Gallagher contributed to this report.