Less than two weeks after Delta Air Lines suffered a systems outage that led to hundreds of canceled flights, passengers on United Airlines are dealing with similar issues after the system that creates flight plans for the carrier experienced technical difficulties.

CBS News reports that third-party program Sabre, which handles the airline’s operations and reservation systems, began experiencing delays around 6 a.m.

As a result, the airline says that “a small number of delays” have occurred across the U.S., but notes that the issue does not constitute a system outage.

“We are working as quickly as we can to resolve it,” the rep tells the Chicago Tribune.

Flight tracking site FlightAware currently shows that 16% — or 291 — of United’s flights are currently delayed.

The site’s misery map shows delays around the country at United’s hub airports: 54 flights are delayed at Chicago’s O’Hare, 37 at Houston, and 30 in Denver.

A number of United customers have aired their frustration with the airline on Twitter (as seen on the right), reporting indefinite delays in boarding and flight departures.

In one exchange, a customer asks the airline if it’s having computer problems again after his flight was delayed and passengers were left sitting on the plane for 30 minutes.

Another United passenger traveling to Chicago reported Tweeted that the captain of his plane had no flight plans, but he had received a text from the airline that it would depart in 40 minutes. In reply, another passenger noted that he’d been on a plane for two and a half hours and that the captain didn’t know when they would eventually leave.

As we noted yesterday a number of factors have contributed to the general appearance that airlines are suffering from massive outages on a frequent basis.

One contributing factor is outdated computer systems and networks that, in some cases, have not been updated or replaced in decades.

Compounding the problem is mass consolidation by U.S. carriers. There are so few airlines serving so many travelers that an outage affecting one airline can now ruin travel plans for thousands of passengers all over the country — all of whom have Twitter and Facebook accounts at the ready for sharing their anger.

Want more consumer news? Visit our parent organization, Consumer Reports, for the latest on scams, recalls, and other consumer issues.