I have used the Xtend Micro Products EmPower compatible adapter for ~ 3 years. My version is a bit bulky, with very heavy cords. The ‘adapter-pc’ connection is a replaceable cable and I believe that you can order a new cable if/when you change PC’s? I also believe that this is the model that is sold in-flight? Mine works fine, and I’ve used it on SQ as they use EmPower as well. (FWIW LH has the easiest implementation; direct AC connection!) Anyway, I would add that I’ve traveled with other FT’ers who’ve used the Targus model (PA360U; ~ $85 USD on-line) and I think that this model/version is much better. It is noticeably lighter, the cables are also lighter and more manageable. And you only have to change the tip (that connects to the PC) in the event that you change notebook models. Were I to replace my adapter I would get a Targus EmPower adapter..

I’ve noticed that lap-top power has been a bit spotty of late. In some seats it might not be working as it may be broken and repairs of this type might not be at the top of the priority list. If the green light is not illuminated, look to see if it is on in other seats. Ask the FA’s to re-set the system.

Also don’t count on UA having the power adapters available for sale on your flight. They might have one, and they might not.

You can test your adapter prior to your flight. These adapters come with a automobile cigarette light adapter, in addition to the EmPower adapter. You can try it out in a car to make sure it works.