Depends on where you’re traveling. Last month, Homeland Security officials announced that passengers flying between the U.S., U.K., Middle East, and East Africa may be required to turn on their electronics at security checkpoints to prove that they’re not hiding an explosive. The specific routes affected haven’t been announced, so all passengers should come to the airport prepared, say officials.

In the event that a device won’t turn on due to low battery charge, you may be required to charge it until it can be turned on. If you don’t have a way to charge it, your options are:
a) toss the device;
b) surrender it to the airline (British Airways and Virgin Atlantic will cover shipping costs); or
c) miss your flight.

The simple solution? In sequential order: 
1) Make sure you charge your devices ahead of time.
2) Pack chargers in your carry-on rather than checked luggage.
3) Just in case, invest in a backup battery.