Originally Posted by GUWonder

CPH is the 18th busiest airport in the world for international travel and has about the same number or a slightly higher number of international passengers than JFK airport in NYC. That said, CPH is far more efficient and passenger-friendly airport to fly to/from/via than most all international airports in the US, including the headache that is generally JFK. (CPH is the only Nordic airport in the top 30 by international passenger numbers and handles more such pax than LAX, Toronto or Zurich.)

For the opposite of "efficient", Miami often takes the cake as one of the most disliked major airports for international passengers in the US.