I'm currently on my flight right now at 35,000 feet.
I plugged in my 180W power supply to the outlet and voila!
My laptop is purrring like a kitty. Display brighten and battery is charging at same rate as at home.
No breaker tripped.
I'm in business class so maybe that's why?
Anyway 787 rocks!
Oh and the overhead ac is pumping in very cool air, so no space heater for my neighbors.