Delta Air Lines is a major US-based international airline, and one of the oldest existing airlines in the world having been founded back in 1925. It is headquartered in Atlanta, Georgia, with eight other major hubs across the US. The airline flies to more than 300 destinations across 52 countries. Delta offers two tiers of first/business class cabins—First Class on short-haul and domestic flights, and Delta One on long-haul international trips. Both of these fares and services consistently receive rave reviews from customers, and its SkyMiles program offers one of the best ways for both domestic and international fliers alike to gain rack up air miles and rewards.