What is the difference between en route and airway?
Enroute: An aircraft that is on its way to its destination.

Air Route: A specific route that an aircraft takes, just like a car route, taking specific highways and roads to get to your destination. Planes do not go a straight line from their origin to destination.

Airway: A highway in the sky. That is what planes fly in their route. So for example 2 planes flying the V23 Airway would have them flying the same path on the airway specifically.