I am a pilot in the US. So my post is primarily from a US point of view. The US follows ICAO airspace designation which consists of: Class A: Instrument Flight Rules, air traffic controlled above 18,000 feet. Class B: Nation’s busiest airports. Requirements to enter: Pilot certification, air traffic control clearance, Mode C transponder. A list of these airports can be found at: http://en.wikipedia.org/wiki/List_of_Cl ... ted_States Class C: Similar to Class B but on a smaller scale. Still very busy airports. Requirements to enter: Established communication with air traffic control, Mode C transponder. A list of the airports can be found at: http://en.wikipedia.org/wiki/List_of_Cl ... ted_States Class D: Smaller airports than B and C but has Tower control. Requirements to enter: Two way communication with air traffic control. Class E: Controlled airspace other than A, B, C, D. These are smaller airports that do not have tower control and most start at 1,200 feet AGL (Above Ground Level). You do not need a radio or a transponder to fly in this airspace. Class G: Uncontrolled Airspace: As the name implies, this is uncontrolled airspace. There are no requirements to fly in this airspace. This airspace even exists over most Class E airports below 1,200 feet AGL or in some cases below 700 feet AGL. Now for the arbitrary nature of DJI’s flight restrictions… If you look at DJI’s restricted zones found at http://www.dji.com/fly-safe/category-mc It looks like most of DJI’s Category A restrictions are over airports with Class B airspace, which are our nation’s busiest airports and the airspace is highly regulated. However DJI’s Category B restrictions are arbitrary. For example in the New York City area, you can find JFK, Newark, and LaGuardia in Category A, but just go West of these in Category B you find 6 airports: Allentown (Class C Airspace) Wilkes-Barre (Class D Airspace) Stewart (Class D Airspace) Binghamton (Class D Airspace) Harrisburg (Class D Airspace) Sullivan County (Class G Uncontrolled below 1,200 feet AGL, Class E above 1,200 feet AGL) It is ridiculous to include an airport like Sullivan County which is uncontrolled airspace below 1,200 feet AGL and not have a restricted area at all around busy airport like Syracuse which is Class C Airspace!!! Or an airport like Danbury or Oxford, CT which are Class D Airspace that are completely unrestricted. It appears that DJI only looked for airports that put the name “International” in the name of the airport. So airports that say “International” even if they are a small airport like Sullivan County with uncontrolled airspace gets a restricted area, while you have a large Class C airspace Syracuse that does not put the name “International” in its name and it’s a completely unrestricted. DJI starts at the top of the aforementioned page, “All unmanned aerial vehicle (UAV) operators should abide by all regulations from such organizations as the ICAO (International Civil Aviation Organization) and their own national airspace regulations.” If DJI wants to reference ICAO airspace, they at least ought to apply their restrictions according to ICAO airspace, and not some arbitrary word in the name of the airport.