Feb. 29 confuses United's software

Passengers using United Airlines' "Easy Check-In" found it anything but that on Leap Day when the automated system failed, resulting in longer lines at its U.S. airport counters.

The airline blamed the service interruption on software issues related to the leap year.

Spokeswoman Megan McCarthy said customers couldn't get Easy Check-In kiosks to confirm that they had been checked in or print out their boarding passes for several hours.

McCarthy said no flights were delayed because of the problem. The airline apologized to customers for any inconvenience.

She said United didn't have any such problems with the software on Leap Day four years ago.