Check the airline you are flying and see if they empower plugs on the planes you will be flying. An adapter can be bought for about $100 that will allow you to work without the worry of the battery life. Even if I only play solitare on some flights I never have to ration my computer time to the battery life. Try booking the bulk head so you don't have to worry about someone leaning into you when they recline.
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Rachel
CO - Platinum
Hilton - Diamond
SPG - Platinum