Bringing US up to code: How outdated software has become a safety issue

When his 6 a.m. flight from Palm Springs, California, to Pittsburgh, was delayed last week Chris Goranson got worried. “I thought something pretty bad must have happened,” says the professor at Carnegie Mellon University’s Heinz College and former federal employee working on modernizing computer systems.

There were no reasons given for the Jan. 11 delay. And the trouble seemed to be spreading nationwide. Although Mr. Goranson experienced only a 90-minute delay in California and another half-hour delay on his connecting flight in Dallas, some 1,300 flights were canceled and another...