It is still important for passengers to use airplane mode when possible while riding on an airplane. The electromagnetic waves from the phone could interfere with the plane’s navigation system. If we’re only talking about a few phones, there would be little chance of interference, however, if all the passengers would allow their phones to remain on, it definitcould present issues with the NAV system and it’s components, such as the autopilot if the FM transceiver.
Once the plane reaches cruising altitude the flight attendants will sometimes announce that it’s now safe to use your phone, but this all depends on how new the plane’s avionics are. Newer avionics are able to deflect the electromagnetic waves produced by phones. Some planes also will have equipment onboard that allows your cellphone to use the plane’s communications systems and you will be able to send and receive emails and texts through the plane’s system. The airplane manufacturers continue to update their capabilities of using cellphones onboard. It’s slowly getting their, but someday, it will be as if you were on the ground.
