While customers would prefer to use the closest airport as an origin or a destination, alternative airports have been increasingly used. The main reason is lower airfare or connections not available at the closest airport. There are two main types of alternative airports:
- Regional alternative airports. As the main airport of a city gets congested with more expensive landing and gate fees, airlines may be looking for alternatives, particularly for those unable to get gate access at the main airport. This is notably the case for low-cost airlines using an alternative airport as part of their cost management strategy to attract customers willing to trade the inconvenience of longer commuting times with lower airfares (and potentially fewer delays). For instance, the low-cost carrier Ryanair uses Charleroi airport to service the Brussels metropolitan area.
- Cross-border alternative airports. Mostly because of differences in regulatory regimes, there may be significant variations in the fare structure between two countries. This provides a strong incentive for passengers to commute (often more than 100 km) to take advantage of lower-cost air transport services in a different country. The most notable example concerns several major Canadian cities close to the American border. Canadian airports have a higher fare structure than American airports because of Federal airport rent, airport improvements fees, and security fees. It can cost twice as much to land the same airplane at a Canadian airport compared to an American airport, resulting in higher average airfare. As an outcome, several American airports close to the border have actively marketed their services to Canadian customers and attracted air connections that they would otherwise not have warranted. Such airport pairs include Vancouver – Bellingham (Washington), Toronto – Niagara / Buffalo, or Montreal – Burlington (Vermont). In 2011, nearly 5 million Canadian passengers took an American border airport instead of a Canadian airport. This process has been labeled cross-border leakage.