A Ticket
Ans 2 - You need valid photo ID (In some cases a driving licence of the country you are in, in others a Passport ) and usually a major credit card.
No, passports are for traveling to other countries.
You need a passport if you are going to travel outside of the country.
To travel inside the US, you typically need a form of identification such as a driver's license or passport.
If you are American you just need your airplane tickets. PR is part of US.
No, you cannot travel inside the US with an expired passport.
About 8 hours
You need to talk to a lawyer about this.
the answer is no. Wales is like a state inside the uk. so if you travel to Wales, or scottland i don't think you need a passport.
For US citizens travelling within US, you just need a valid government issued photo ID, you can use your passport for this.
If you are looking to travel from cities only inside the country of the US then just have valid identification cards with you like your SSS ID. However, if it is an overseas travel or travelling abroad, then a passport is needed.
If you are taking an airplane than yes. Just because Puerto Rico is America's property doesn't mean you don't need a passport to get there.
As long as you have a proof of your legal stay in the US then you can travel by airplane to another state, but it is preferable to travel with your Visa already there especially when you are traveling by Air.