The Magical Science of Wi-Fi on Airplanes

How we browse the internet at 35,000 feet

Sarvesh Mathi
Published in
7 min readNov 22, 2019


Credit: Colin Anderson Productions pty ltd/Getty Images

SSurfing the internet at 35,000 feet is now something that we expect on flights. According to the 2018 Global Traveler study, 94% of global travelers feel that inflight internet would enhance their travel experience and 30% of them explicitly look for this feature when booking their flight.

Source: 2018 Global Traveler Study

Currently, airlines make $17 per passenger for services like inflight food and retail. Inflight Wi-Fi will add $4 to this ancillary revenue and is estimated to bring in $30 billion in additional revenue for airlines by 2035.

Given these stats, it’s not surprising to see airlines around the world rushing to add inflight Wi-Fi to their list of amenities. But how does an airline deliver this modern luxury to flyers who are cruising at nearly 560 mph at more than 6 miles above sea level?

There are two ways for the internet to reach planes:

Air to ground (ATG) system

This system, the first to be developed, works like the ground-based mobile data network you’re accustomed to through your cell phone. But unlike mobile towers that focus signal downward, the towers meant to provide internet to planes project them upward. Antennas fitted under the belly of the plane receive the signal and send them to the onboard server. This server has a modem that converts radio frequency signals into computer signals and vice versa, providing access to passengers through the Wi-Fi access points installed inside the aircraft. Information is exchanged between the plane antenna and the towers along the path of the flight. The towers, in turn, are connected to operation centers run by the service providers which are similar to the control centers of your broadband ISP.

Ground-based towers projecting signal upward. Source: ThePointsGuy