Well, there are some airplanes these days that have plugs for use so people can power their electronics.
Yes, you can bring your laptop charger on an airplane in your carry-on luggage.
No. Even if a laptop has internet, it does not work while flying on an airplane, because there is no Wi-Fi on an airplane, or in the sky.
yes you may
The only authorized means of using a laptop for airplane travel is to disable the wireless transmitter (done through your operating system or a button/toggle switch on the laptop itself).
sleep or get a laptop.
To ensure compatibility between your airplane laptop charger and the power outlets on board, check the voltage requirements of your charger and the power outlets on the plane. Most airplanes provide power outlets with a voltage of around 110-120V, so make sure your charger is compatible with this range. Additionally, consider using a universal adapter or converter if needed to ensure a proper connection.
Well on AirFrance you can take a hp laptop. I don't know about others.
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Yes, you will need to take the laptop out of your carry on when you go through security.
Every laptop has a different power rating.
Polaroid PDV-0700 Portable DVD Player is a cheap laptop you can purchase to watch DVDs on an airplane. You can read its review at shira.net/tech-portabledvd.htm.
There are some power adapters that are designed for use on airplanes, but they are expensive and only offer a short addition to battery life.