Getting to and around any busy airport requires insight and planning — especially these days, with more people flying and increased security measures. Here's a selection of some of the world's largest and most-used airports, with a few hints to make getting there more efficient and getting around a little easier.

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Flying to one of these busy airports? Follow these tips. — Klaus Lahnstein/Getty Images

1: London Heathrow Airport

Traveling to Heathrow, the world's third-largest airport (in passenger numbers), is easy by public transport — much faster than a cab. The Heathrow Express, which departs from central London's Paddington Station, is a much-lauded, super-fast train, but you might find that the Piccadilly Line on the Underground (subway) is more convenient, as it has more stops travelling through the city. It's also much cheaper than the express. Before heading out, though, check the Transport for London website, specifying the correct airport terminal in your search: Terminals 1-3, 4 and 5 are three separate buildings, each with its own Underground station. On weekends, some stations — and even some lines — are closed for maintenance. If so, you'll need to allow extra time for transit along alternate routes or on buses. All five terminals have a good selection of eating and drinking outlets — Pret a Manger has neat little sushi boxes, great for a snack on the plane.

2: Beijing Capital International Airport

In 2011, this was the world's second-busiest airport, and the number of passengers and flights using it are increasing rapidly each year. Arriving and leaving Beijing Capital International Airport is straightforward, with express trains heading between Dongzhimen (central Beijing) and Terminals 2 and 3. If you're in transit with a long layover, consider paying to use one of the hourly hotel-style lounges in Terminal 3, located on the west side of the arrivals hall. These have TVs and Internet access as well as beds and shower rooms, and are open 24 hours a day.

3: Atlanta Hartsfield-Jackson

Thankfully, the world's largest airport, known as a hub for U.S. domestic flights, has an efficient way of moving you between terminals. The PlaneTrain APM (Automated People Mover) connects the domestic and international terminals with the airport's seven concourses. Although Atlanta's airport isn't necessarily known for its dining, it's worth checking in early for a meal at the One Flew South restaurant in the international Terminal E. The menu has such contemporary dishes as pecan-dusted scallops and pan-roasted pork loin with mustard greens. Check in online before arriving at this busy airport to avoid spending precious time in lines waiting to get a boarding pass.

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