I'm flying for 9 hours, how do I save my iPhone 4S battery life?

I'll be flying to New York in a week, how do I make sure my iPhone battery won't die in the first 2 hours like normal?

TURN THE BRIGHTNESS Way DOWN
It's like 75% of what consumes battery life.

Https://www.google.com/search?q=portable+phone+charger&oq=portable+phone+&aqs=chrome.0.0j69i57j5j0.5362j0&sourceid=chrome&ie=UTF-8

Airlines ask you to turn off your phone during the flight anyways and with the power off, you won't have to worry about draining the battery.

Turn it off. Really, are you that dumb?

Pilsner Man nailed it: Shut it off. Easy as pie.

Enjoy your flight.

Like Pilsner Man said, turn your phone off. Simple.

WRONG FORUM. Ask in the Cell Phones & Plans category.

First I have to point out that the phone has to be turned off from the time the cabin doors close until the pilot announces that electronics can be used, and then it must be in airplane mode. You can't use it as phone, but you can use to listen to music, play games, etc.

Airplane mode will help with power consumption, as it turns off all the broadcast functions, and they use a great deal of power. Dimming the screen will also help. Beyond that, just watch the battery level, and turn it off and stow it once you get down to minimal power so you can power it up after landing.

Turn it off.