Final answer:
When flying through Class D airspace, you must establish two-way communication with the air traffic control (ATC) facility responsible for that airspace.
Step-by-step explanation:
In aviation, airspace is classified into different classes based on the level of control and restrictions imposed. Class D airspace is one of these classifications. When flying through Class D airspace, you must establish two-way communication with the air traffic control (ATC) facility responsible for that airspace. This means you need to contact the ATC and follow their instructions for entering and navigating through the airspace.