FAA: Outage caused by contract workers unintentionally deleting files

The big picture: The outage of the system that sends pilots safety alerts and other critical information caused thousands of delays and cancellations and cost airlines billions of dollars.

Details: The FAA, which is still investigating the outage, has so far found no evidence of a cyber-attack or malicious intent, per the agency.

• They've made the necessary repairs to the system and taken steps to make the Notice to Air Missions System system more resilient, according to the statement.

What they're saying: "The agency is acting quickly to adopt any other lessons learned in our efforts to ensure the continuing robustness of the nation’s air traffic control system," the FAA said.