There are three main categories: open, specific and certified. Most drone flights take place in the open category. In this category, all drones are assigned a class (C0 to C4), which in turn determines the operating class (A1 to A3). As of 2023, drones in the open category are no longer permitted to fly over assemblies of people. If your drone does not have a class identification label, you are subject to slightly different rules.