Washington Dulles International Airport (IAD) is a fairly quirky airport. One of its most famous traits is the presence of mobile lounges, which are essentially large buses that transport passengers between concourses and from arriving international aircraft to customs. The passenger carriage can be raised to the height of aircraft, and it was meant to usher in a new era of modernity for the international airport serving America’s capital city. Decades after they were introduced, almost everyone hates them.

Ultimately, the lounges were designed before jet bridges and people movers became widespread, and these proved more effective at transporting passengers between different parts of an airport. But whereas these have been phased out at almost every airport where they were operated, the mobile lounges remain in use at Dulles. With much of the airport’s infrastructure aging and at capacity, the Metropolitan Washington Airports Authority finally approved a modernization and overhaul plan for IAD, which will include the retirement of the mobile lounges.

Where IAD Currently Stands

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Dulles is the primary international airport serving Washington, DC, competing somewhat against Ronald Reagan Washington National Airport (DCA), which only handles short-haul flights. It serves as a fortress hub for United Airlines, which uses it as a secondary hub for transatlantic flights to complement its Newark operations. It currently has four runways with a fifth planned. In addition, the airport features a main building with ticketing, baggage claim, and customs, along with two mid-field buildings featuring two concourses each.

Designed by Finnish-American architect Eero Saarinen, the Main Terminal is regarded as Saarinen’s best work and has remained largely the same as when it first opened in 1962, but has been extended. The satellite building housing Concourses A/B is used for all non-United flights, while some United Express flights fly out of Concourse A, and is connected to the Main Terminal as well as to Concourse C by the AeroTrain.

The building housing Concourses C/D (used by United), however, was intended to be temporary, yet it’s remained in use for decades. It’s small and aging, while Concourse D lacks an AeroTrain connection. All gates in this building can be used for international departures, while only Concourse C is used for international arrivals.

The airport currently operates 49 mobile lounges, split between 19 original vehicles dating back to the early 1960s and 30 ‘PlaneMates’ that date back to the 1970s. Today, they are used to transport passengers to Concourse D, as well as to take passengers to the International Arrivals Building. They’re slow, outdated, and frequently overcrowded, making them disliked by passengers and even executives like United CEO Scott Kirby. This is why they’re finally set to be replaced.

The Modernization Of Dulles Airport

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The building containing Concourses A and B is still functional while still being relatively modern, having opened in the late 1990s. However, the satellite terminal containing Concourses C and D was built in the 1980s as a temporary facility, yet it’s never been replaced. Although the building was updated in the 2000s, the ceilings are low, space is limited, dining/retail options are limited, and the facility is reliant on the mobile lounges. This is problematic for United Airlines, as it’s the sole tenant at Concourses C and D.

However, in August 2026, the Metropolitan Washington Airports Authority approved a $22.5 billion redevelopment plan for IAD. The Main Terminal will be expanded beginning in late 2027 for $6.2 billion, while the building housing Concourses A and B will be expanded and renamed as just Concourse A. Concourse E, which is set to open soon, will be renamed as Concourse C and expanded, while a new building will be constructed south of this facility known as Concourse D. Finally, the temporary concourses will be demolished and replaced by a new Concourse B.

A new pedestrian tunnel will be built to link the Main Terminal with all four concourses, while the AeroTrain will be expanded to connect all concourses. Once this is completed, the mobile lounges will finally be retired, but this won’t occur until 2034, or over 70 years since they were first introduced. In the meantime, the mobile lounges are getting life-extension upgrades and will remain in their current role until the airport’s upgrades are completed.

The New Concourse E Coming To IAD

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On October 8, 2026, Dulles Airport will host a ribbon-cutting ceremony for the new Concourse E, a project that first began construction in 2024. The first phase of the concourse will feature 14 gates used by United Airlines, along with 17 new concession stands, a United Club, and an AeroTrain station. Although only a small portion of United’s IAD flights will use Concourse E at first, it will represent a major upgrade for the airline’s passengers given the age and overcrowding of Concourses C/D.

Concourse E will be expanded with more gates and is also slated to receive a separate Customs and Border Protection (CBP) facility, alleviating overcrowding from the current CBP facility in Concourse C and the International Arrivals Building. In addition, prior plans included an expansion to the building that would have been dubbed Concourse F, but current plans now call for the whole building to be called Concourse C. In the future, IAD plans to add 22 new gates to this facility.

While United will be the main airline operating out of Concourse E, it will concentrate most international flights out of Concourse A. This is the closest concourse to the International Arrivals Building, and this will shorten walking times for international passengers. In addition, United will be constructing a new Polaris lounge along the connector linking the Main Terminal to Concourses A/B. Once the current Concourse C/D building is demolished, the International Arrivals Building and Concourse E will host the only CBP facilities at IAD.

The Impact Of The New Redevelopment Plan

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United Airlines is the largest airline operating out of IAD, but it’s limited by the fact that domestic travelers tend to prefer nearby DCA and that its nearby Newark hub simply has far higher local demand. However, although there are some minor market issues, the carrier has also faced efficiency issues due to the aging facilities. United had a significant say in the published plans for IAD’s growth and is therefore the primary beneficiary of the new facilities, as it will use most of the gates being added.

United CEO Scott Kirby has been promoting his airline as the US’s flag carrier recently, and the airline is notable for being the only carrier with an international hub in DC. United is thereby stating that the new facilities will further enable it to serve this role more effectively while presenting a better experience for travelers visiting the country’s capital city. These plans work even better for United when considering that the carrier is planning to double the size of its international footprint out of IAD.

Newark will remain a larger long-haul hub for the carrier because of the size of the New York market, but crucially, United is becoming increasingly capacity constrained out of this airport. It’s running out of room to grow, and this is also true for the other airlines that operate New York hubs. This is partially why secondary hubs like American’s Philadelphia operations, Delta’s Boston operations, and the IAD hub are important, and the value of the Dulles hub will only increase in the future.

Cost Concerns About The Expansion

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At $22.5 billion, the expansion plans for IAD are tremendously expensive, especially considering that its passenger numbers are relatively modest; 2025 saw around 29 million passengers pass through the airport. As a point of comparison, Boston Logan International Airport (BOS) handles over 43 million passengers per year, while Denver International Airport (DEN) handles well over 82 million passengers annually. It’s therefore a very expensive project for an airport that is ultimately far from the busiest in the country.

It’s been speculated that, due to the cost of the project, airlines could end up paying as much as $90 per enplanement through higher airport fees. This would potentially lead to higher airfares, while budget airlines, which have generally been struggling in the US, could end up being pushed out of IAD. Scott Kirby, however, has dismissed concerns about rising enplanement costs, pointing out that the expansion will result in more flights. The increased costs would end up being spread across more passengers as a result.

Meanwhile, although the MWAA has approved funding for the expansion, it has not awarded the main contract for the construction of the new facilities. It’s expected that these will be awarded in early 2027, while construction for the Main Terminal’s expansion will start in late 2027. As such, it’s important to note that the design concepts are not yet finalized and could change in the future.