Why airplane mode? Onboard electronics, interference and Wi-Fi on planes

“Please switch your electronic devices to airplane mode.” You have probably heard that announcement many times, and you have probably wondered whether a single phone can really throw an airliner off. The short answer: very likely not – and there are still good reasons for the rule. This article explains why airplane mode is required on board, what has changed in the rules in recent years and how Wi-Fi and cellular service work at 10,000 meters in the first place.

Why airplane mode? The short answer

Airplane mode switches off all radio transmitters of your device: cellular for sure, and depending on the device also Wi-Fi, Bluetooth and NFC. The camera, gallery, music, e-books and offline maps keep working. It is required for two reasons:

1. Caution toward the onboard electronics. A phone that is searching for a network transmits at high power. Modern avionics are well protected, but the authorities do not want an avoidable residual risk, especially in critical phases of flight.
2. Consideration for the mobile networks on the ground. From high altitude, a phone “sees” a great many cells at once and jumps back and forth between them at high speed. Ground networks are not built for that.

On top of that comes a very practical effect: a phone that searches in vain for a network for hours drains its battery quickly.

What airplane mode switches off technically

A smartphone has several radio modules: the cellular modem (GSM, UMTS, LTE, 5G), Wi-Fi, Bluetooth and often NFC. Airplane mode shuts them all down at first. On most current devices you can then turn Wi-Fi and Bluetooth back on individually while the cellular modem stays off – exactly this combination is what many airlines allow.

What usually keeps running in airplane mode is the GPS receiver. It transmits nothing and only listens to the satellite signals. Whether your device shows its position in airplane mode depends on the manufacturer and the settings. For the map view you need offline maps loaded beforehand anyway, since you have no internet.

Reason 1: interference with onboard electronics

The worry about radio interference is older than the mobile phone. As early as 1961, the US aviation authority restricted the use of FM radios on board because their receivers can emit spurious signals that cause problems for VOR navigation. In 1966 the rule was extended to all portable electronic devices.

With the mobile phone came a device on board that does not just receive but transmits strongly itself. The signals can couple into the cable harnesses and antennas of onboard systems. Studies reached mixed results: a 2000 study by the British aviation authority CAA found that a phone near older avionics can exceed limit values. Measurements on scheduled flights in the early 2000s showed that GPS receivers in particular can react sensitively to radio sources in the cabin. As things stand today, there is no accident that has been clearly traced back to a passenger device.

The effect is noticeable in the cockpit, though. Many pilots know the characteristic buzzing in the headsets that GSM phones produce when setting up a connection – the same noise you know from speakers when a phone lies next to them. It is not dangerous, but it disturbs exactly when the crew is concentrating on the radio during the approach. How voice radio is built up is explained in the article Understanding air traffic radio frequencies.

Why takeoff and landing in particular?

Most navigation and landing systems work by radio. On an ILS approach, radio beams guide the aircraft onto the runway, radar altimeters measure the height above ground, and the transponder reports position and altitude to air traffic control. In these phases the aircraft is close to the ground, and there is little time to react to a false reading. That is why the strictest rules traditionally applied there – and why the crew can still, in rare cases such as approaches in very poor visibility, require devices to be switched off completely today.

Reason 2: the mobile networks on the ground

The second reason is often overlooked but is at least as important. Mobile networks divide their frequencies among many small cells. Neighboring cells use different channels, more distant ones reuse the same. That works as long as a phone reaches only a few cells in its surroundings.

At several kilometers of altitude, a phone has a clear line of sight to a great many base stations at once. It registers here, then there, the aircraft keeps flying at several hundred kilometers per hour, and the networks have to process handovers constantly. On top of that, the phone works at high transmit power because of the distance. For ground networks designed for pedestrians and cars, that is a disruptive factor. That is exactly why the US communications regulator FCC banned using the cellular network in the air in the early 1990s – the ban has less to do with flight safety than with the radio network.

What is allowed today: the rules at a glance

For decades the rule was: everything off at takeoff and landing. That changed fundamentally in 2013. On October 31, 2013, the US agency FAA declared that airlines can allow passengers to use portable devices in all phases of flight, provided they have shown that their aircraft are insensitive to them. Phone calls over the cellular network remained excluded. The European agency EASA followed on December 9, 2013, and allowed devices in airplane mode during the entire flight. In September 2014, EASA went one step further and opened the way for devices to stay switched on without airplane mode under certain conditions.

In practice, that does not mean every airline allows everything. The authorities set the framework, and the airline decides what applies on its fleet.

Situation	Typical rule at European airlines	Note
Smartphone in airplane mode	allowed in all phases of flight	large devices such as laptops are usually stowed at takeoff and landing
Wi-Fi on board	allowed if the aircraft offers it	often only enabled from cruising altitude
Bluetooth headphones and smartwatch	usually allowed	follow the airline’s rules
Cellular via cabin base station	only if the aircraft is equipped	only from 3,000 m above ground, calls often blocked
Cellular without airplane mode	depends on the airline, often prohibited	crew announcement takes precedence

Regardless of all rules: the crew’s instruction is binding. Anyone who ignores the request to switch off a device on board risks trouble that can go far beyond a warning. The same goes for other cabin rules around takeoff and landing, which the article Window shades, seat backs and lighting at takeoff and landing explains.

Cellular on board: the base station in the cabin

The reason you still get a signal in some aircraft is a small base station of its own in the cabin, a so-called picocell. Your phone connects to it instead of to the towers on the ground. Because the station is only a few meters away, the phones transmit at very low power. A control system also prevents devices in the cabin from registering with ground networks. The connection to the outside then runs via satellite.

In the EU, a Commission decision from 2008 regulates this service. Among other things, it requires that the system may only transmit from 3,000 meters above ground. At the end of 2022, the Commission added 5G to the rules, and the member states had to release the frequencies for it by June 30, 2023 at the latest. Since then, airlines can also offer 5G via the cabin base station.

The idea is not new. Emirates enabled calls on board on selected flights as early as March 2008, and Ryanair launched a cellular service on part of its Dublin-based fleet in February 2009 – an early experiment that did not catch on at the airline. Whether you may make calls today is up to the airline. Many deliberately allow only messages and mobile data to keep the cabin quiet.

Wi-Fi on planes: satellite or ground network

Onboard Wi-Fi works differently from your router at home. There are perfectly ordinary Wi-Fi access points in the cabin, but the actual connection to the internet runs one of two ways.

A European example is the European Aviation Network, built jointly by Deutsche Telekom and Inmarsat. It combines around 300 LTE ground stations in the EU, Switzerland, the UK and Norway with a satellite as a supplement, for example over the sea. It launched commercially in 2018 with the International Airlines Group as launch customer, which includes British Airways, among others. The ground stations are adapted for aircraft, among other things for high speeds and large cell radii. In 2025, IAG announced it would switch more than 500 aircraft to Starlink – a sign of how fast the market is moving right now.

For you as a passenger, that means: whether onboard Wi-Fi is free, only good enough for messages or allows streaming depends on the airline, fare and aircraft. And Wi-Fi works even when your phone is in airplane mode – you simply turn Wi-Fi back on.

Airplane mode from a spotter’s perspective

For spotters, a flight is not a lost day, quite the opposite. Airplane mode takes little away from you:

• Photos and videos work without restriction. How to get clean pictures through the window is covered in Photographing from the airplane window, which seat is worth it in Choosing the best window seat for photos.
• GPS keeps running on many devices. That puts coordinates in the image data, which makes later identification easier – more on this in Adding GPS data to photos.
• Offline maps show you which airports, cities and landscapes you are flying over right now, if you download them before departure.
• Battery you save because the phone does not constantly search for a network. That pays off if you still want to go to the fence after landing.

Live flight tracking on your own route, on the other hand, only works with onboard Wi-Fi. Your phone cannot receive the ADS-B signals of other aircraft itself. If you photograph with your smartphone while traveling, you will find tips in Plane spotting with a smartphone, and what camera gear you can get through security is covered in Camera gear in carry-on luggage.

What to keep in mind

• Airplane mode before the door closes. At the latest when the crew asks for it, not only while taxiing to the runway.
• Stow large devices. At takeoff and landing, many airlines require laptops and tablets to go in the overhead bin or under the seat – less because of radio than because of the risk of injury in an abrupt maneuver.
• Wi-Fi and Bluetooth only if allowed. The airline’s announcement counts, not the option in your device’s settings.
• Download maps and entertainment beforehand. Onboard Wi-Fi is not available on every route and not always fast.
• Follow the crew’s announcements. Even though rules differ between airlines: on board, the crew decides.

Conclusion

Airplane mode is less scaremongering than many think, but also no relic without a reason. Modern aircraft can cope with a forgotten phone, yet aviation generally takes no avoidable risk in the takeoff and landing phases – and the mobile networks on the ground benefit from hundreds of phones not searching for a network from altitude at the same time. Since 2013 you may use your devices in airplane mode in all phases of flight, and Wi-Fi and cellular on board run through dedicated systems built for exactly this purpose.