CHICAGO -- United Airlines had to stop flying Wednesday for about an hour due to a computer glitch.
Everything was working as of 5 p.m. Wednesday, but in the last year nearly every major airline has had these problems, impacting thousands of passengers.
Aviation expert Joe Schwieterman says the problem is airlines have not been able to duplicate their complex computer systems. So when it goes down even for an hour it can ground flights nationwide. It is becoming an almost routine problem for airlines: computer systems crash and flight after flight is canceled until it can get fixed.
"I can't remember a 6-month period in my life time this many glitches driven by internal airline problems," Schwieterman said.
A professor at DePaul, Schwieterman says part of the problem is there are less airlines due to mergers, so flights are more full, and they are working with old technology.
"Airlines are feeling the pressure, they are pushing their equipment to max those gates constantly, so when things get out of kilter it's harder for them to adjust; that's why the pain can drag on for days," he said.
That pressure is coming from Wall Street and airlines' bottom lines. Ground stoppages can cost airlines hundreds of millions of dollars. Airlines are also pouring millions into fixing their complex systems and duplicating them.
"A year ago airlines were saying these duplication systems were almost perfect. Now they are backing off of those claims, saying 'we cant get our arms around this to solve this like we thought,'" he said.
He believes airlines are at least 1-2 years away from duplicating their systems, and while it may be painful for passengers to sit through these ground stops, he doesn't believe their safety is at risk or that hacking is an issue.
"We are so dependent on air travel that when you bring a system down like that, it affects commerce in ways we couldn't imagine," Schwieterman said.
A security expert also pointed out airlines have a unique problem that other companies don't have: They can't just shut down for the weekend and go to work on their system. He says for airlines it's like trying to fix the plane when it's in flight.