London Heathrow Airport (LHR) is undeniably the largest and most important airport in the United Kingdom, a facility through which millions of passengers will travel annually. The airport is the principal hub for British Airways, the United Kingdom’s flag carrier, as well as Virgin Atlantic, a major international airline that collaborates extensively on flights across the North Atlantic with US-based legacy carrier Delta Air Lines. In addition, the airport is served extensively by airlines from across the world, many of which have multiple daily flights from the massive facility.