In theory, no. However, due to increased security in recent years, airlines will not allow passengers to board an aircraft without acceptable photo ID. The most acceptable form of ID is a valid passport.
yes you do
Yes you do. If you leave out of state you need a passport
yes
Not from Northern Ireland as it is a part of the UK.
You do not need a passport to fly from London to Newcastle-upon-Tyne, as both locations are in the UK, however it is always best to take your passport with you just in case.
Yes, always.
No you need a passport.
No. There is a common travel agreement between Ireland and Britain.
Yes, your passport.
That will depend on your nationality and where you are coming from. Generally though, for any international travel you should have a passport.
It is regarded as an internal flight, but you should bring a passport with you any time you are flying.
If you are from another country yes. But if you are just from another city in Ireland then of course not.
No sorry