American Airlines has the shortest overall stage length of the so-called US Big Three carriers, partly influenced by having the fewest long-haul services. Its typical flight covers just 720 nautical miles (1,333 km). In contrast, 
Delta Air Lines is 826 nautical miles (1,530 km), and 
United Airlines is 921 nautical miles (1,706 km). Regional units, which are vital for connectivity, are included in all three cases.