Question

what is the meaning of the foreign expression in bold? when thunderstorms broke out in the region, air traffic controllers at the riverside airport scrambled to redirect flights already en route to riverside to other nearby airports. exiting moving back about to depart on the way

Explanation:

The phrase "en route" is a French loanphrase commonly used in English to describe something or someone that is in the process of traveling to a destination. In the context of flights, it means the flights are already traveling toward Riverside airport.

Answer:

on the way