During every flight passengers are given serious-sounding instructions to either turn off their phone or switch it to airplane mode.
While most people comply with the policy, many are unsure why.
Could sending a quick text or updating your Facebook status really cause harm to the plane?
Wales Online have answered all your questions, revealing why airlines are so strict.
Why are we asked to switch to flight-safe modes?
Airlines ask passengers to switch laptops, e-readers, tablets and mobile phones to flight safe mode to protect equipment in the cockpit from electromagnetic interference.
The type of interference that can be caused by a mobile phone can sometimes be heard when a call or text message is sent or received by a phone that is placed near a household audio system.
Airlines are mainly concerned with reducing the risk of interference during take off and landing when clear communication lines between the cockpit and air traffic control is critical.
So how bad is it?
While the interference from one mobile device is likely to be minimal, a cumulative affect could be caused by many phones emitting signals at the same time.
According to Neil O’Connor, a senior network specialist at Zurich Airport, improved technology and aircraft manufacture has reduced the risk of interference in recent years.
Mr O’Connor said: “As standards of electrical devices have vastly improved over the years, electromagnetic interference is greatly reduced.
“Aircraft structure has also been improved to be able to shield from electromagnetic interference.
“Some airlines even have their own on board wifi network which allows you to connect to their in flight entertainment using your own device.”
So do I still need to switch it off?
Although forgetting to turn your e-reader off is unlikely to cause a plane to plummet out of the sky, it’s still important to listen to advice given by cabin staff.
Even small interferences can cause annoyance and delays in communication that may not be dangerous under ordinary circumstances, but could disturb a pilot’s work.
Switching the phone off is courteous and the safest course of action when flying.