Though if you enter a game that runs since a long time, be sure to find a HQ without a well-established opponent. Which may mean a smaller airport, but, at least, noone will prevent you from initial growth. If you plan to play several game years, better take an area with several interesting airports(The EU, USA, China.....).
Normal game worlds, globally, are more punitive on night landings & take-offs, and have more competitive opponents. When you have a 737 making good money on a 300NM routes with 130 demand, and then a newcomer arrives with 3 daily S2000 flights and low prices(and he makes profit anyways), you know you're not in a beginner's game, and you'll have to find your profit elsewhere.