What is controlled airspace?  After all, a lot of "controlled" airspace is actually not under direct control at all, right? Well let's start with the definition right out of the Aeronautical Information Manual (AIM): 3−2−1. General a. Controlled Airspace. A generic term that covers the different classification of airspace (Class A, Class B, Class C, Class D, and Class E … [Read more...] about What is Controlled Airspace? (AIM 3-2-1)