Perhaps not since the Sept. 11, 2001, attacks have the spacious skies over America been as empty as they were Wednesday morning when the Federal Aviation Administration ordered all domestic flights grounded over a computer malfunction. The cause wasn’t immediately identified, but this is the second time in two weeks that major disruptions have occurred in the air transportation system related to aging computer systems that experts have long warned are in need of an upgrade.
What plagued Southwest Airlines in late December, experts say, was a computer and software system…
