Duluth is a small city in USA. The city has low tourism and business ratings ranging from 50-125.
The default airport is Duluth Int'l Airport (DLH).
It isn't surprising why this airport gets very little use. Beginners and strongly discoraged from starting here due to its extremely low ratings, which will bring minimal profits. The only routes out of Duluth that will make a decent profit are routes to big cities such as Chicago. Although there will usually be none, any competition routes here should be closed as the city cannot sustain any form of competition. Its location provides good access to major American cities, such as Detroit and Chicago.
Duluth Int'l Airport is usually empty and will never achieve a status greater than Level 1. Obviously, buying or building airports here is a complete waste and should always be avoided.
Never fly large planes out of Duluth as they will depreciate. Use small-sized or medium-sized planes to fly to nearby big cities in order to maximize profits.