Changi Airport in Singapore is my favorite international airport. It consistently impresses me with its exceptional customer service, cleanliness, efficiency, and the wide range of activities and amenities available, such as the butterfly garden, cinema, and even a slide! Regarding the second part of the question, Changi Airport ranks among the busiest airports in the world. It accommodates over 100 airlines, and I would estimate that around 170,000 to 200,000 passengers arrive and depart each day. This estimate takes into account approximately 7,000 non-stop flights each week and its status as a major global hub city.