I searched but since this is still a pretty new device I haven't found a solution. I was on a flight yestarday and was watching a movie with my noise-cancelling headphones but the volume just was not there. I could pick up most of it but really struggling. I know my 6800 had reg. "adjustments" that could be made to affect the volume, does anybody know how to do it on this phone yet?

Thanks in advance, I really appreciate the help I get in this forum!

I know of one option you can consider. Headroom makes portable amps especially made as headphone amplifiers.

PROS: They make very good quality stuff. I don't have one of the portable units, but I do own one of their micro DAC/AMP systems and it is great quality on sound. This unit will amplify your movie or music and is made for use with headphones. It runs on 4 AAA batteries.
CONS: You will have another device to carry around with you. Since it uses batteries (last 20 hr), that is one more thing to charge or purchase. Their base unit cost $99 which isn't pocket change. Depending on your headphone specs, you may also be needing a new headset to handle the higher power (ask them for advice)

Headroom Total Airhead - Headphone Amplifier | HeadRoom Audio

Doesn't the Verizon model include the program Audio Booster in Programs?

EEEH, I do not think I would want another piece of HW between my phone and my head. I think Bundo is right about that app, if not there are regedits that will help here. If all else fails, you can buy amplified headphones - they are not common, but do exist.

I use a set of ear buds that are made to block out noise (walmart, $18 - not sure of the brand) - they work like ear protection and are made of that foam that seals in your ear. They are not noise-canceling, they just seal to your ear canal, thus blocking out other noises. I can mow my lawn with the volume at 65% and still hear music or an audio book perfectly.

This is also a better solution as you are not just blasting your ear drums with EVEN more decibels. I love finishing yard work (or any other loud work for that matter) without the loud ringing that lasts for a half an hour. Best $18 I ever spent.

PS - I looked and the model I am using is a JVC brand HA-FX34 - I am sure there are many others, but these sound great and the price is right.