Originally Posted by SFO 1K

Sorry, unlike AA, UA hasn't had power in the economy cabin until the introduction of the p.s. product. Since your flight options did not include p.s. flights, you'll need a well charged battery and maybe a back-up one too, for your transcon trip.

If your flight is operated by a 767-200 aircraft, there's not even a benefit in upgrading to business class for power, as the 762s do not have power either. If it's a 767-300, you would be able to use an empower adapter for an AC connection to your computer.