Nearly $5 billion is being pumped into the continuing renovations at Dulles International and Baltimore-Washington International airports. Among the projects: a new terminal, high-tech underground trains, modernized runways and overall improved services for passengers.

BWI

The biggest project by far is the construction of a new BWI terminal. The new Terminal A will be connected to the current Terminal B, which is home to Southwest Airlines, and will provide an additional 11 gates for the airline (for a total of 26). The new terminal is scheduled to open in the spring, according to Jonathan Dean, communications manager for the Maryland Aviation Administration. The terminal, part of the airport's $1.8 billion renovation and expansion, will include enhanced security screening, additional baggage carousels and more restaurants and shops.

Already, BWI has opened an 8,400-spot daily parking garage and debuted skywalks from the hourly garage to the terminal. There's also a new consolidated rental car facility, and parts of the airport have been refurbished.

For the next two years, the main roads around BWI will undergo expansion, which in the meantime means that some lanes are or will be closed. For wandering drivers awaiting the arrival of a loved one's flight, that normally would mean frustratingly clogged lanes. To alleviate that stress, drivers can park for free for an hour in the garage across from the terminal or pull into the free 50-space "cell phone lot" to await the call that the plane has landed.

Dulles

Passengers will soon start to wean themselves from the airport's notorious "mobile lounges," those crowded shuttle vehicles that cart people from the main terminal to remote concourses. A moving walkway is scheduled to debut by Thanksgiving, allowing passengers to reach concourses A and B without having to take the mobile lounge, said Tara Hamilton, public affairs manager for the Metropolitan Washington Airports Authority.

By 2009, most shuttles will be replaced, largely by an underground train system (though the mobile lounges will still be used to take passengers to planes not parked near the concourses). The tunnels for those trains are being built now, which is why the security screening areas on the west side of the airport are closed (though the security clearance areas at that end of the terminal have been moved, so the number of checkpoints is the same). A 325-foot control tower also is being built, and outdated ticket counters and aged baggage claim areas are being upgraded as well.

For four months this year, one of Dulles's three runways was closed. It was torn up and replaced and reopened last month. Eventually, two more runways will be constructed, with the first scheduled to open in four years.

-- Elissa Leibowitz