EDINBURGH/MADRID/BALTIMORE, July 19 (Reuters) - Air

passengers worldwide faced delays, flight cancellations and

headaches checking in as airports and airlines were caught up in

a massive IT outage that has affected numerous industries

ranging from banks to media companies.

A software update by global cybersecurity firm CrowdStrike ( CRWD )

triggered systems problems for Microsoft ( MSFT )

customers that turned into hours of delays for airlines using

their software. Some travelers were issued handwritten boarding

passes with software inoperative.

All told, out of more than 110,000 scheduled commercial

flights on Friday, 5,000 have been cancelled globally with more

expected, according to global aviation analytics firm Cirium. By

comparison, 2,000 flights were cancelled on Thursday, before the

software issues.

The aviation sector is particularly sensitive to

interruptions due to its reliance on closely coordinated

schedules run by air-traffic control. Delays can throw off

schedules for airports and airlines for the rest of the day.

U.S. carrier Delta Air Lines ( DAL ) was one of the hardest-

hit, with 20% of its flights cancelled, according to flight

tracking service FlightAware.

Across the United States, Asia and Europe, carriers such as

Ryanair, United and Air India said they had

faced delays or disruption.

"Nobody was around to tell us where we could check in when

we arrived ... so different groups queued in different places

and then in the end someone, after a bottleneck of people was

formed, told us to come here," said Ana Rodriguez, a tourist

from Mexico, while waiting for a flight in Madrid's Barajas

Airport.

Even airlines that were not directly affected said they

would have to grapple with delays due to the global nature of

the disruption.

Transportation system issues appeared to be resolving and

would be hopefully be back to normal by Saturday, said U.S.

Transportation Secretary Pete Buttigieg, adding that the U.S.

Federal Aviation Administration did not appear affected.

FLIGHT DISRUPTIONS

Atlanta's Hartsfield-Jackson airport, one of the world's

busiest and a hub for Delta Air, had the worst disruptions

globally, according to FlightRadar24, with 36% of scheduled

departures cancelled.

Delta resumed some flight departures but warned of

additional delays and cancellations. FAA data showed Delta's

operations in Atlanta, Minneapolis and New York were still

affected. Customers who had flights cancelled were issued travel

waivers, the airline said.

United said the disruption affected systems used for

calculating aircraft weight, check-ins, and its call centers.

In Europe, Spanish carrier Iberia said it had managed to

avoid flight cancellations. Ryanair had cancelled 2% of its

flights, while 38% of its scheduled flights were delayed.

HANDWRITTEN BOARDING PASSES

The outage sparked chaos for European passengers on what was

one of the busiest travel days of the year as schools broke up

for holiday.

In Edinburgh, a Reuters witness said boarding-pass scanners

carried a "server offline message," with the airport saying

passengers should not travel to the airport without checking

their flight status first. Amsterdam's Schiphol airport, Berlin

airport and London Gatwick were also affected.

In India, airlines at New Delhi's Terminal 3 were giving

handwritten boarding passes to flyers, while airport staff were

using whiteboards to display gate information, according to an

official for the airport. Airports in Hong Kong and Singapore

also switched to manual check-in.

At Baltimore/Washington International Thurgood Marshall

Airport in Baltimore, Maryland, Rose Geffrard, 37, a nurse

travelling with her two children to a cousin's wedding in

Boston, said she spent nearly two hours waiting in a long line

to get paper tickets.

Spirit Airlines ( SAVE ) personnel had to page through

printed passenger manifests before issuing paper tickets and

then consulted a printed seating chart to make sure they were

not double assigning seats.

COMPENSATION QUESTIONS

In Europe, airlines are required to compensate passengers

for delays of more than three hours but it was unclear to what

extent they would be held legally responsible for the outage.

Airlines would have to prove the outage was an extraordinary

circumstance to not compensate passengers, a spokesperson for

European consumer organization BEUC said.

Major U.S. airlines in 2022 committed to providing meals for

customers delayed by three hours and hotel rooms for stranded

passengers if prompted by issues under the airlines' control.

Unlike in Europe, there is no legal requirement that

airlines in the United States compensate passengers for lengthy

delays. It is also not clear if the IT issue will be deemed an

airline-caused delay or not.