“Mobile phone signals can interfere with aircraft navigational and landing guidance systems.” The relationship between phone signals and navigational systems is not an exact science, which is why everyone we spoke to was careful in their language.

If you use your cellular data on a plane, the most likely outcome is that your battery will drain rapidly as the phone struggles to find a signal from ground towers moving at 500 mph. While it is a common myth that a cell phone will cause a plane to "fall out of the sky," the real concern is Electromagnetic Interference (EMI). Your phone's signal could theoretically cause a "buzzing" or clicking sound in the pilots' headsets, similar to the noise an old speaker makes when a phone is nearby, which can distract them during critical phases of flight like landing. Additionally, the FCC prohibits it to prevent "clogging" ground-based cell towers. In 2026, many European flights now allow 5G usage via "picocells" (mini-towers on the plane), but in the U.S., the FAA still requires Airplane Mode to protect sensitive radio altimeters from potential 5G interference.