Many flights across the world have been delayed or canceled Friday because of a major IT system failure.

All flights for US carriers United Airlines, Delta Air Lines, and American Airlines were grounded early on Friday before operations started ramping up again.

American Airlines has confirmed that is has resolved the issue affecting its operations, while Delta and United have resumed some flights.

The Federal Aviation Administration provided assistance to airlines with ground stops as the IT issue was being addressed, the agency said early Friday morning on X.

“Currently FAA operations are not impacted by the global IT issue,” the FAA posted later on Friday. “We continue to monitor the situation closely.” The agency also said the IT issue “could continue to affect flights this weekend.”

As of midday Friday, thousands of flights had been canceled globally, with chaotic scenes at airports across the world as passengers waited for updates.

Here are some of the major airlines and airports that have been impacted by the tech outage:

Impacted airlines and airports

The situation is evolving quickly, and passengers should check flights directly with carriers. The following are some of the carriers and airports with known technology impacts:

North America

American Airlines, United Airlines and Delta Air Lines were all impacted and issued travel waivers on Friday.

“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. We apologize to our customers for the inconvenience,” American Airlines said in a statement to CNN.

Delta and United resumed some flights Friday morning and warned of additional disruptions throughout the day.

“The issue affected many separate systems, such as those used for calculating aircraft weight, checking in customers, and phone systems in our call centers,” United Airlines said in a midday update.

Ultra-low cost airline SunCountry, Allegiant Air, Frontier and Spirit Airlines were experiencing disruptions caused by the outage on Friday.

Southwest Airlines and JetBlue were not impacted by the outage.

“While our operational systems were not impacted by this outage, 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,” JetBlue said in a statement.

Toronto-based Porter Airlines announced that it was canceling flights on Friday until noon ET due to “prolonged third-party technology systems outages affecting multiple global industries.

Two low-cost airlines in Mexico City, Volaris and Viva Aerobus, were also impacted.

Passengers traveling through Los Angeles International Airport are experiencing a “mixed bag” of delays and cancellations due to the tech outage, an airport spokesperson told CNN.

At Hartsfield-Jackson Atlanta International Airport airside operations are working, although some customer-facing airlines “are dealing with a few challenges,” amid the ongoing global computer outage, Andrew Gobeil, who oversees public affairs outreach at the airport, told CNN.

At Dallas Fort Worth International Airport officials “anticipate significant delays and cancellations throughout the day,” the airport said. “We ask customers to verify your flight status with your airline prior to heading to the airport. Longer lines are possible so allow extra time.”

Chicago O’Hare International Airport advised passengers to check their flight status directly with their carrier due to the tech issues. “Longer lines and wait times are possible, please allow extra time,” it said.

John F. Kennedy International Airport said: “The Port Authority is not affected by the ongoing global network outage, but some airlines are experiencing delays/cancellations. DO NOT head to the airport unless your flight status is confirmed,” according to an airport post on X. That guidance applies to LaGuardia and Newark airports as well.

Philadelphia International Airport said passengers should expect delays and cancellations on Friday.

Charlotte Douglas International Airport advised passengers not to come to the airport “unless they have confirmed their flight information with the airline.”

Miami International Airport advised that US Customs and Border Patrol operations are being affected nationwide, “so international passenger arrivals are currently being processed manually at a slower pace.”

Around the world

Asia Pacific

In the Asia Pacific region, AirAsia’s “core reservation and check-in system” was impacted and Cebu Pacific Air was forced to handle all processes manually.

Singapore Airlines, the flag carrier of Singapore, said none of its flights had been impacted, but it is experiencing technical difficulties.

Qantas, the flag carrier of Australia, has also been impacted by IT disruptions, and was still operating Friday, but with delays.

Taiwan’s Taoyuan International Airport said several airlines at the airport had been impacted. Jetstar, Hong Kong Express, Jeju Air and Scoot have all resorted to manual check-ins, the airport said.

Delhi’s Indira Gandhi International Airport and six Indian airlines have also reported technical difficulties. Jaipur International Airport said “flights nationwide” have been affected by the outage.

South Korea’s Incheon International Airport said Air Premia, Easter Jet and several other airlines had been affected. Korean Air, the country’s flagship carrier, said it uses Amazon Web Services (AWS) and so had not been affected.

Middle East

Dubai International Airport said the check-in process for some airlines had been affected, but that it is “now back to operating normally.”

Europe

London’s Gatwick Airport said it is “affected by the global Microsoft issues” and that passengers may experience delays checking in and going through security.

Germany’s Berlin Airport said it is experiencing delays to check-in due to a “technical fault.”

Amsterdam’s Schiphol Airport said the “global system failure” had affected “flights to and from Schiphol” and the impact is “now being mapped.” KLM Royal Dutch Airlines said the outages are “making flight handling impossible.”

Scotland’s Edinburgh Airport said the outages mean “wait times are longer than usual at the airport.”

Spain’s airport authority, AENA, which supervises airports in Madrid, Barcelona and others across the country said the outage “could cause delays” and that its staff are working to solve the problems. Iberia Airlines, the flag carrier of Spain’s airline, told CNN their systems started working again at 9:30 a.m. local time (3:30 a.m. ET), adding there were still some delays.

Prague Airport said the issues have affected its global check-in system, delaying flights.

Ireland’s Ryanair also confirmed a disruption to the airline’s network, advising passengers to arrive at least three hours before their scheduled departure time.

Air France, the country’s flag carrier, said the IT issue had disrupted its operations — although flights already in the air are not affected.

Turkish Airlines said it was experiencing problems with ticketing, check-in and reservations. “Our teams are working diligently to resolve the issue,” the airline said.

Central and South America

Panama-based Copa Airlines said it is also one of the global airlines impacted and some flights might be delayed following the large-scale third-party software outage, according to a post on X on Friday. The airline asked passengers to “go to the airport at least 4 hours before your departure.”

LATAM Airlines, the Chilean carrier, announced on Friday that global outages “could be causing delays” for some its flights.