Delta outage highlights vulnerabilities of airline industry

Delta Airlines said additional delays and cancellations are expected Tuesday after its massive computer meltdown. About 1,000 flights were cancelled Monday - at one point, only six flights were in the air over the U.S - after a power outage knocked out Delta's computers and left thousands of travelers stranded.

But the whole industry is now under new scrutiny after Delta's network outage, raising questions about the reliability of computer systems used by airlines that are not regulated by the FAA, reports CBS News correspondent Kris Van Cleave.

The outage disabled Delta's flight status alerts.

"We found out that we're four hours delayed. And by the time we get to our connecting flight in LaGuardia, we're going to be an hour late," said passenger Shanese Sims.

And airport monitors incorrectly listed flights as on time, prompting an apology from Delta's CEO.

"It's an all-hands-on-deck effort. We lost power about 2:30 this morning, which caused us to implement the ground stop that we put in place," said Ed Bastian.

Delta is still trying to figure out exactly what caused the system-wide meltdown. Early indications suggest a piece of equipment known as a switchgear may have failed, knocking out computer networks worldwide. But that raises another question - why didn't the backup systems kick in?

According to travel industry analyst Henry Harteveldt, Delta's backup systems shouldn't have failed.

"That's unacceptable to the traveling public, and it's unacceptable to Delta and its employees," Harteveldt said.

But Delta is just the latest to join other airlines that have suffered technical malfunctions. Last year, United and American both suffered computer problems, and in July, a faulty router forced Southwest to ground flights - a disruption that lasted days.

Harteveldt blames them on the antiquated computer system used by airlines.

"They're running on a reservation system that is more than 35 years old. In fact, it once belonged to an airline that went out of business in 1982," Harteveldt explained.

"I think a lot of airlines haven't spent enough on their technology over the years and this is why we're seeing things like this more often," said George Hobica, founder of Airfarewatchdog.com.

Airlines now rely on computers to handle everything from reservations and seat assignments, to how much fuel and snacks to load on a plane.

Harteveldt said Delta has been rebuilding its core technologies for more than six months. The airline industry generally has reliable systems, but portions can be decades old.

"Airlines are technology companies that fly airplanes. Their technology systems have to be as reliable as their aircraft," Harteveldt said.

The Department of Transportation told CBS News that it was in discussion with Delta regarding the technical issues and continues to monitor the situation.

Delta is offering a $200 voucher to anyone whose flight was scrapped or delayed three hours or more.