Yes, in airplane mode. Most airlines require airplane mode for takeoff and landing; once airborne you can usually turn Wi-Fi and Bluetooth back on if the plane offers them. Cellular calls are still banned on almost all flights. Follow the crew's instructions.
Phones are fine on board — the rule is about the cellular radio, not the device.
Airplane mode: required by most airlines throughout the flight. It disables cellular signal, which airlines and regulators keep restricted (the interference risk is small, but the rule remains and constant tower-switching at altitude is pointless anyway).
Wi-Fi and Bluetooth: on most aircraft you can re-enable them after takeoff — airplane mode plus Wi-Fi on is the normal setup for onboard internet and wireless earbuds.
Phone calls: banned on virtually all flights worldwide, even where Wi-Fi calling would technically work. A handful of carriers in some regions allow limited in-flight cellular, but assume no.
Practical tips: download entertainment and offline maps before you fly, put the phone in airplane mode at the gate, and keep it charged — many seats now have USB power.
Related questions
Is Wi-Fi free on flights?
Sometimes. A growing number of airlines offer free Wi-Fi (often via a loyalty-program or carrier partnership), but most still charge, especially on long-haul. Messaging is frequently free even when full internet isn't. Check your airline before you count on it, and download entertainment first. Full answer →
How do I survive a long-haul flight?
Choose your seat deliberately, dress in layers, drink water and skip alcohol, walk every two hours, download entertainment in advance, bring your own snacks, and plan sleep around the destination's clock. Compression socks help on flights over eight hours. Full answer →
Airline, airport and government rules change without notice. Treat this as a starting point and confirm with the airline or authority for your specific trip. Request a correction if something is out of date.