A computer system glitch left thousands of United Airlines passengers across the globe grounded Wednesday, causing a ripple effect of heavy delays throughout major airports.
About 3,500 flights were affected and the airline sought to recover after the ground stop was lifted. Aviation experts said that delays of even 90 minutes could have a snowball effect triggering flight delays at each late flight's destination.
"Its going to not only affect flights in air but all flights on the ground," Anthony Roman, a former pilot and president of Roman & Associates, a private investigation and risk-management consultancy told MSNBC. "They have flights in gates that should be occupied by another flight."
The delays could reach 235 domestic and 138 international destinations.
"We experienced a network connectivity issue this morning," United confirmed in a statement after 9 a.m. "We are working to resolve this and apologize to our customers for any inconvenience."
The Federal Aviation Administration specifically blamed the ground stop on "automation issues."
Aviation experts said the day's events could prove costly for United Airlines which has worked to regain its footing and worked out most problems in merging with Continental Airlines.
The airline is offering affected customers a waiver on its website to change flights.
The ground stop was lifted around 9:20 a.m. for United's regional carriers, which can perform their own weight and balance checks.
Passengers at airports from Albuquerque, New Mexico, to Washington, D.C., to Florida complained of system backups and long lines. Gate agents at some locations were forced to write tickets by hand.
NBC Connecticut said United passengers without a hard copy of their boarding pass were not being allowed to check in at Bradley International Airport in Windsor Locks, north of Hartford.
And former Massachusetts senator Scott Brown said, via Twitter, that he and other customers were receiving conflicting information from the airline.
This is a breaking news story. Please check back for updates.