Guam is a protectorate of the USA, but is out of the country. I think you will need one.
You can check at the post office.
yes
A passport.
None needed to travel within the US.
A passport is not needed to fly from one US state to another. However, you will need a photo ID of some sort to board the plane.
Yes, you do not need a passport to fly to the US Virgin Islands if you are a US citizen.
Passport is a requisit.
Yes, you can use a foreign passport to fly in the US as long as it is valid and meets the entry requirements set by the US government.
You can fly to Mexico, but, you won't be able to fly back to the US.
Seeing as Texas and Louisiana are both US States, no you do need a passport to fly between them.
No, only when you leave the borders of the US.
No. To fly an airplane you need a pilot's license. To fly on an airplane within the USA, NTSA guidelines require a passport (foreign or US), US passport card, or US drivers license or non-drivers license.
YES