Millions of Americans woke up Wednesday morning to find out they weren't going anywhere. Around 6:30 a.m., the Federal Aviation Administration (FAA) announced that its Notice to Air Missions (NOTAM) system had failed. By 9 a.m. the ground stop was lifted, but the damage was already done. Thousands of flights were

It appears that the NOTAM outage was the result of a system failure, but the nation's critical infrastructure faces a range of threats—everything from Russian hackers, to weather events, to angry individuals with guns. So, the failure and subsequent air travel chaos brought on by this latest cyber failure could serve as a real-life demonstration of what might happen if risks to critical infrastructure systems are left unaddressed.

It is too early to know the exact causes and consequences of the NOTAM failure, but two things are clear: It was bad, and it could have been worse.