Come next year, it will be battle of the terminals at London's Heathrow Airport (www.heathrowairport.com/). Terminal 3, home to Virgin Atlantic (www.virgin-atlantic.com/), is currently undergoing a revamp, while the brand-new Terminal 5, home to British Airways (www.britishairways.com/), is being constructed. Although both carriers are touting things like new lounges and railway stations, the amenity customers are most looking forward to is a faster and more efficient check-in process.

In fact, Virgin Atlantic, which will be the first to debut its terminal later this year, said that fast, efficient and stress-free check-in are the three key factors for passengers, according to internal research.

The most prominent feature of T3, which has been designed by Foster + Partners in conjunction with Virgin Atlantic, is its "Upper-Class Drive-Thru Check-In." This allows for first and business class passengers to be chauffeured up a curved ramp directly to the terminal, where they will be greeted by a Virgin Atlantic host who will complete all the formalities of check-in, including document checks and some security questions, while the passenger is still in the car. From there, passengers proceed to security, through to the Clubhouse and then onto the gate. For economy passengers, the airline is providing online and kiosk check-in.

"We estimate that it will take the majority of our passengers under 15 minutes to check in and get through to the departure lounge and even less time for our upper class passengers to get to the Clubhouse," said Steve Ridgeway, chief executive for Virgin Atlantic. "[This is] in contrast to most of British Airways' long-haul passengers, who will have a longer journey through the vast T5."

And though that might be a knock against the competition, it is true; T5 promises to be huge, as the entire site—also consisting of 60 aircraft stands, two satellite buildings and a parking garage—is roughly the size of Hyde Park. Designed by the Richard Rogers Partnership, T5 will feature six new lounge areas, retail shops like Harrods, Paul Smith and Tiffany & Co., as well as its own railway station with six platforms: two for Heathrow Express, two for the London Underground's Piccadilly Line and two built as a future link to AirTrack.

British Airways also says that T5's baggage system is the biggest, single-terminal baggage handling system in Europe. Transfers and late bags will be assigned a priority routing through a separate high-speed baggage system and be delivered directly to the aircraft stand of the departing flight.

In the hopes of easing aircraft operations, British Airways has exclusive use of T5 aircraft parking stands. The carrier points out that the terminal also is close to T3, which—in addition to Virgin Atlantic—houses BA's Oneworld alliance partners Qantas, Iberia and Finnair airlines. T5 makes its official debut next March, though British Airways will begin operating there as a trial run in September.

Both Virgin Atlantic and British Airways offer direct service between London Heathrow and major American cities such as Boston, Chicago, Los Angeles, Miami and New York, so it seems the battle of the terminal buildings will be won based on passenger preference. And even then, only the frequent flier miles may know for sure.