No

A cyber attack is a cyber operation, whether offensive or defensive, that is reasonably expected to cause injury or death to persons or damage or destruction to objects.

Michael Schmitt et al; Tallinn Manual 1.0, pp 92
  • Cyber Operation?
  • Expected to cause death or injury to people or damage to objects?
A Russian DDoS of US Airport Websites does not match this definition. Here's a list of actual cyberattacks and and why this matters.

What happened?

Russian-speaking hackers are claiming credit for a Distributed Denial of Service (DDoS) operation against a some US airports’ websites offline. The attack caused intermittent outages with LaGuardia Airport’s website, for 15 minutes starting about 3 a.m., according to a Port Authority spokesperson. There was no impact to airline or airport operations

Los Angles International Airport, New York LaGuardia, Chicago O’Hare and Hartsfield-Jackson Atlanta International Airport all had similar temporary intermittent disruptions to public websites.

Earlier this year, in March, the same group, Killnet, also claimed credit for a Denial of Service operation against a regional airport in Connecticut.