Editing Dulles International Airport (section)

==== Later developments ====
By 1985 the original design, featuring [[mobile lounge]]s to meet each plane, was no longer well-suited to Dulles's role as a hub airport. Instead, midfield concourses were constructed 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; Concourse C/D was the first to be built, followed by Concourse A/B. A tunnel (consisting of a passenger walkway and moving sidewalks) that links the main terminal and Concourse B was opened in 2004.<ref name="walkway">{{cite web |year=2009 |title=Passenger Walkway to Concourses A and B Fact Sheet |url=http://www.mwaa.com/File/WalkwaytoAandB.pdf |url-status=dead |archive-url=https://web.archive.org/web/20110105171622/http://www.mwaa.com/file/WalkwaytoAandB.pdf |archive-date=January 5, 2011 |access-date=October 12, 2010 |publisher=Metropolitan Washington Airports Authority |df=mdy-all}}</ref> The [[Metropolitan Washington Airports Authority]] (MWAA) began a renovation program for the airport including a new security mezzanine with more room for lines.<ref name="Improvement">{{cite web |year=2009 |title=Dulles Development: Main Terminal Improvement Fact Sheet |url=http://www.mwaa.com/File/MainTerminal.pdf |url-status=dead |archive-url=https://web.archive.org/web/20110105171755/http://www.mwaa.com/file/mainterminal.pdf |archive-date=January 5, 2011 |access-date=October 12, 2010 |publisher=Metropolitan Washington Airports Authority |df=mdy-all}}</ref>

A new train system, dubbed [[AeroTrain (Washington Dulles International Airport)|AeroTrain]] and developed by [[Mitsubishi Heavy Industries|Mitsubishi]], began in 2010 to transport passengers between the concourses and the main terminal.<ref name="aerotrain">{{cite web |title=Aerotrain – How the System Works |url=http://www.mwaa.com/sites/default/files/archive/mwaa.com/file/at2_how_system_works.pdf |url-status=live |archive-url=https://web.archive.org/web/20160304190105/http://www.mwaa.com/sites/default/files/archive/mwaa.com/file/at2_how_system_works.pdf |archive-date=March 4, 2016 |access-date=September 14, 2015 |publisher=Metropolitan Washington Airports Authority}}</ref> The system, which uses rubber tires and travels along a fixed underground guideway,<ref name="aerotrain" /> is similar to the people mover systems at [[Singapore Changi Airport]],<ref name="aerotrain" /> [[Hartsfield–Jackson Atlanta International Airport]], and [[Denver International Airport]]. The train is intended to replace the mobile lounges, which many passengers found crowded and inconvenient. The initial phase includes the main terminal station, a permanent Concourse A station, a permanent Concourse B station, a permanent midfield concourse station (with access to the current temporary C concourse via a tunnel with moving walkways), and a maintenance facility.<ref name="aerotrain" /> Mobile lounges continue to service Concourse D from both the main terminal and Concourse A. Even after AeroTrain is built out and the replacement Concourses C and D are built, the mobile lounges and plane mates will still continue to be used, to transport international arriving passengers to the International Arrivals Building, as well as transport passengers to aircraft parked on hardstands without direct access to jet bridges. Dulles has stated that the wait time for a train does not exceed four minutes, compared to the average 15-minute wait and travel time for mobile lounges.{{citation needed|date=November 2022}}

Under the development plan, future phases would see the addition of several new midfield concourses and a new south terminal.<ref>{{cite news |last=Weiss |first=Eric M. |date=August 19, 2008 |title=Dulles Updates Its People Movers |url=https://www.washingtonpost.com/wp-dyn/content/article/2008/08/18/AR2008081801349.html |url-status=live |archive-url=https://web.archive.org/web/20121111131422/http://www.washingtonpost.com/wp-dyn/content/article/2008/08/18/AR2008081801349.html |archive-date=November 11, 2012 |access-date=October 12, 2010 |newspaper=[[The Washington Post]]}}</ref> A fourth runway (parallel to the existing runways 1 and 19 L&R) opened in 2008,<ref name="4thRunway">{{cite web |year=2009 |title=D2 Projects: Fourth Runway |url=http://www.mwaa.com/dulles/773.htm |url-status=dead |archive-url=https://web.archive.org/web/20100929191207/http://mwaa.com/dulles/773.htm |archive-date=September 29, 2010 |access-date=October 12, 2010 |publisher=Metropolitan Washington Airport Authority |df=mdy-all}}</ref> and development plans include a fifth runway to parallel the existing runway 12–30.<ref name="5thRunway">{{cite web |year=2009 |title=D2 Projects: Future Fifth Runway |url=http://www.mwaa.com/dulles/771.htm |url-status=dead |archive-url=https://web.archive.org/web/20100930002554/http://mwaa.com/dulles/771.htm |archive-date=September 30, 2010 |access-date=October 12, 2010 |publisher=Metropolitan Washington Airport Authority |df=mdy-all}}</ref> If this runway is built, the current runway will be re-designated as 12L-30R while the new runway will be designated 12R-30L. An expansion of the B concourse, used by many low-cost airlines as well as international arrivals, has been completed, and the building housing Concourses C and D will eventually be knocked down to make room for a more ergonomic building. Because Concourses C and D are temporary concourses, the only way to get to those concourses is via moving walkway from the Concourse C station, which is built in the location of the future gates and Concourse D by mobile lounge from the main terminal.<ref name="WUSA">{{cite news |last=Fox |first=Peggy |date=January 25, 2010 |title=Dulles Airport To Open AeroTrain |url=http://www.wusa9.com/news/local/story.aspx?storyid=96354 |url-status=dead |archive-url=https://web.archive.org/web/20111208171346/http://www.wusa9.com/news/local/story.aspx?storyid=96354 |archive-date=December 8, 2011 |access-date=October 12, 2010 |work=9 News Now |publisher=[[WUSA (TV)|WUSA]]}}</ref><ref name="D2 Project AeroTrain">{{cite web |title=D2 Projects: AeroTrain System |url=http://www.mwaa.com/dulles/d2_dulles_development_2/projects/aerotrain_system_2 |url-status=dead |archive-url=https://web.archive.org/web/20071113154733/http://www.mwaa.com/dulles/d2_dulles_development_2/projects/aerotrain_system_2 |archive-date=November 13, 2007 |access-date=January 10, 2008 |work=Metropolitan Washington Airports Authority}}</ref>

[[File:Escalators near departure zones 3 and 4 at Dulles International Airport.jpg|thumb|The interior of the main terminal, showing the escalators leading to baggage claim and arrivals]]
In the short term, [[United Airlines]] has constructed a {{convert|20000|sqfoot}} buildout on Concourse C between gate C18 and the AeroTrain entrance for use as a Polaris Lounge for international passengers.<ref>{{cite web |last=Russell |first=Edward |date=December 10, 2018 |title=United to invest at least $34m at Washington Dulles |url=https://www.flightglobal.com/news/articles/united-to-invest-at-least-34m-at-washington-dulles-454288 |url-status=live |archive-url=https://web.archive.org/web/20181211131636/https://www.flightglobal.com/news/articles/united-to-invest-at-least-34m-at-washington-dulles-454288/ |archive-date=December 11, 2018 |access-date=December 16, 2018 |website=Flight Global}}</ref> Further expansion plans include a new three-story {{convert| 550000|sqfoot}} south concourse building above the AeroTrain station for Concourse C,<ref name="D2 Project AeroTrain" /> to replace Concourse A regional gates built in 1999.<ref>{{cite web |date=July 7, 2021 |title=Dulles Airport's Ambitious Expansion Continues with New United Concourse |url=https://airlineweekly.com/2021/07/united-airlines-may-finally-get-a-new-concourse-in-washington/ |url-status=live |archive-url=https://web.archive.org/web/20210825214159/https://airlineweekly.com/2021/07/united-airlines-may-finally-get-a-new-concourse-in-washington/ |archive-date=August 25, 2021 |access-date=August 25, 2021}}</ref>

Decades-old rules set by Congress that limit the number of takeoffs and landings, as well as distance of routes, at Reagan Airport were intended in part to keep more flights at Dulles. Those rules have been weakened by Congress over the years, however, causing Dulles to lose 200,000 passengers to Reagan between 2011 and 2013.<ref name="wapo112714" />

In 2023, construction started on a 100 MW solar power facility, battery and bus charging equipment.<ref>{{cite web |last1=Casey |first1=J. P. |date=23 August 2023 |title=Dominion Energy and MWAA begin construction of 100MW solar facility at Dulles airport |url=https://www.pv-tech.org/dominion-energy-and-mwaa-begin-construction-of-100mw-solar-facility-at-dulles-airport/ |url-status=live |archive-url=https://web.archive.org/web/20230827173837/https://www.pv-tech.org/dominion-energy-and-mwaa-begin-construction-of-100mw-solar-facility-at-dulles-airport/ |archive-date=August 27, 2023 |access-date=August 27, 2023 |website=PV Tech}}</ref> It would include the largest airport-based solar and battery development in the U.S. as part of an agreement with Dominion Energy. The solar panels would cover more than {{convert|835|acres|ha}} on land, equivalent to the consumption of more than 37,000 Northern Virginia homes during peak production.<ref>{{Cite news |title=Dulles solar farm would be the nation's largest at an airport |url=https://www.washingtonpost.com/transportation/2022/08/12/dulles-airport-solar-farm/ |url-status=live |archive-url=https://web.archive.org/web/20220814115117/https://www.washingtonpost.com/transportation/2022/08/12/dulles-airport-solar-farm/ |archive-date=August 14, 2022 |access-date=2022-08-14 |newspaper=Washington Post |language=en-US |issn=0190-8286}}</ref>