Can I turn on my cell phone after the plane takes off?

No.

Any radio communication equipment needs to occupy a certain spectrum resource for communication. If there are other radio signals on this spectrum, they will interfere with each other and cause errors in the judgment of the received signals.

For civil aviation, absolute safety is required, which means that radio contact must be absolutely correct and reliable, so no interference is allowed within the radio navigation frequency band.

Extended information:

EASA stated that electronic devices such as mobile phones can be turned on during the flight of civil aviation aircraft, but each airline needs to conduct its own assessment to confirm that the aircraft The system is not affected by signals from handheld electronic devices and then develops its own execution guidelines. This means that the implementation of this new regulation on some airlines may be delayed.

Previously, EASA stipulated that passengers must set their mobile phones to flight mode during the flight.

Reference: The maximum fine for using mobile phones after takeoff is 50,000 yuan_Sina News?