Madam Chair, the approach to classifying drones has varied depending on the regulation in question. With regard to drone registration, for example, there is an exemption for drones weighing less than 250 grams, which really captures a lot of what we would commonly consider to be toy drones. Those don't need to be registered, and everything above that weight threshold up to about 25 kilos or 55 pounds does need to be registered.
The approach that was taken in the committee I referred to, which focused on drone flights over people, by and large categorized drones based on risk factors associated with impact energy, except for a very low category, which was weight-based, of 250 grams and below. As we considered the risks and issues related to drones flying over people, the key parameter really was impact energy. In its upcoming rule-making, the U.S. FAA will presumably take an approach whereby they specify impact energy levels and break out drones in different categories, all in the small UAS or UAF realm of 55 pounds and under.