NEW YORK • A computer router error that grounded hundreds of United Airlines flights on Wednesday is just a preview of what can go wrong for carriers with increasingly automated operations, experts said.

As airlines switch to electronic luggage tags and more travellers swop paper tickets for boarding passes stored on smartphones, industry consultants say the impact of technology disruptions will keep growing. That means more money lost for airlines and more travel plans thwarted for passengers when a glitch occurs.

"Airlines are flying computers," said industry analyst Henry Harte- veldt. "Increased reliance on technology has enabled (airlines) to become a much more successful and efficient business, and that also creates an exposure."

The disruption at United, which locked the airline out of its reservations records and therefore blocked check-in and boarding, led to delays for tens of thousands of travellers.

This was the second technical problem in about one month to ground United's fleet. On June 2, software needed to dispatch the airline's flight plan briefly lost functionality.

American Airlines flights were delayed just a month earlier because of an application problem on pilots' iPads, which recently replaced paper flight manuals.

To be sure, technology has brought benefits like shorter wait times for check-in and more in-flight entertainment via Wi-Fi.

Consultant and former American Airlines executive Scott Nason said the number of outages had not increased with automation.

"The difference," he said, "is that when they occur, they can more easily affect the airlines' ability to actually fly." REUTERS