Washington Dulles International Airport 1980s the original design, featuring mobile lounges to meet each plane, was no longer well-suited to Dulles' role as a hub airport. Instead, midfield concourses were added to allow passengers to walk between connecting flights without visiting the main terminal. Mobile lounges were still used for international flights and to transport passengers between the midfield concourses and the main terminal. An underground tunnel (consisting of a passenger walkway and moving sidewalks) which links the main terminal and Concourse B was opened in 2004. The Metropolitan Washington Airports Authority (MWAA) began a renovation program for the airport including a new security
London City Airport Authority. London City Airport has a single long runway, and a CAA Public Use Aerodrome Licence (Number P728) that allows flights for the public transport of passengers or for flight training (but only for training necessary for the operation of aircraft at the airport). Only multi-engine, fixed-wing aircraft with special aircraft and aircrew certification to fly 5.5° approaches are allowed to conduct operations at London City Airport. The largest aircraft which can be used at the airport is the Airbus A220-100. London City served over 4.5 million passengers in 2017. It is the fifth-busiest airport in passengers and aircraft movements