In the USA, Commercial pilots are expected to follow the specifications of the FAA’s Part 107 Small UAS Rule (Part 107), which contains passing the FAA’s Aeronautical Knowledge Test to gain a Remote Pilot Certificate.
Hobbyists are expected to follow the FAA’s recreational model aircraft rules. One of the rules is that if the drone weighs more than 0.55 lbs (250g), then the users need to pay $5 to get it registered.
In Europe, the European Union (EU) does not control the civilian use of remotely piloted aircraft (RPA) with a mass of 150 kg or less. These aircrafts are overseen by national rules accepted by the EU Member States. RPAs above the threshold of 150 kg fall within the directive of the European Aviation Safety Agency (EASA).
In the UK, the limitations are still pretty upfront. Drones are included under English laws, including aviation laws, which are regulated by the Civil Aviation Authority (CAA). UAVs that weigh 20 kg or less are covered by articles 166 and 167 of the Air Navigation Order. Drones with cameras must not be flown within 150 meters of a jammed area in UK, or within 50 meters of a person, vessel, vehicle, or any other construction that is not under the pilot’s control. Any person using a drone for commercial purposes must attain a license from the CAA.
In Australia, small commercial drone operators do not have to pay the current $1,400 in regulatory fees. All the landholders could fly drones of up to 25 kg on their properties without the any approvals.