None.
Yes, there have been instances where US citizens have been denied entry to the UK for various reasons, such as not meeting entry requirements or having a criminal record.
If you are a US citizen, there are no transit restrictions if you're arriving from the mainland. If you are a non-us citizen and arriving from anywhere other than the mainland US, the same restrictions (if any) apply as if you were landing at any other US port of entry.
Yes, a US citizen can be denied entry into their own country if they have committed certain crimes or if there are concerns about their security or health.
born in USA...
it is no different from flying to another state, (as Hawaii is a state). Hawaii has stricter agricultural rules though.
Sure, there are no restrictions on marriage. However, being married does not automatically change one's visa status or citizenship. Make sure you understand the requirements to become a legal resident so that you are not separated from your spouse by INS!
As a US citizen traveling to the UK, you will need a valid passport and may also need a visa depending on the purpose and length of your stay. Make sure to check the UK government website for the most up-to-date information on entry requirements and any travel restrictions in place, such as COVID-19 related regulations. It's important to be prepared and comply with all necessary documentation to ensure a smooth entry into the UK.
Yes, a US citizen can be denied entry into the United States under certain circumstances, such as if they have committed a serious crime or if there are concerns about their health or security risks.
Yes, as long as the British citizen has not committed a crime or is otherwise ineligible for entry into the US.
The US President must be a US citizen, naturally born on US soil. Congress does not have this requirement.
None, unless the country where the US citizen has requirements for long stays that have not been met by that citizen.
Yes, there have been instances where US citizens have been denied entry to the US, typically due to issues with their documentation or legal status.