I have only ever used battery power while travelling on an aircraft with my laptop. I have got some long haul flights coming up mainly with Etihad. My power supply is universal voltages and has worked in Europe the far east and the USA OK. I also have an adaptor which allows me to run it form my car.

What cable do I need to power my laptop from an aircraft? Does it vary by airline?

Can anyone give me any advice on what I need to buy?