Originally Posted by
teddybear99
OP,
As stated above, you will need parental permission to travel outside the USA, also since you are considered a minor, the airlines may have further requirements as well, so you should check with each airline as well.
Entering the UK, I would suggest having a certified letter from the parents of your girlfriend inviting you to stay at their home as well as the contact information in case the UK Immigration Officials want to call and confirm this personally. Also, if something were to go wrong with the relationship, and they ask you to leave, where would you stay while awaiting your return to the USA. Also they may ask for some proof that the relationship was initiated in person, and is not one of communication by internet only. This might include pictures of you and your girlfriend.
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This is simply untrue. The US does ot require parental permission to travel outside the US. If OP has a passport, both his parents or his custodial parent if he has one, have signed that application. It has been this way for at least 15 years and the urban myth just creates hassles.
What OP ought to do is carefully review what he will need for the UK and make certain that everything is for real. As others suggest, proving that he has the means to support himself in the UK, that he has a place to stay (address + mobile numbers so GF's parents can be reached), return ticket to the US (which he has), and a plausible story to show that this isn't some crazy fraud.
Finally, medical care. At age 17, who will authorize it and who will pay for it if something happens? The UK has a nationalized health service, so the government is paying and it needs to be assured that it will be paid back, presumably by a US insurer. So, have that information. You may have an insurance card. If you don't your parents ought to be able to obtain one for you presuming that they cover you. As to who can authorize medical care, make sure that you have mobile numbers for parents/relatives back in the US so that if something does happen, you can be treated. This isn't a situation where you would want your parents authorizing your GF's parents, never having met them, to handle medical decisions, should something happen to you. Remember, this isn't just about major catastrophes. This is about the many little things that can go wrong when you are far from home.
The UK's interest here is that it does not wish to be stuck with the care of a minor when things go wrong. At age 17, he is old enough to be put back on a plane to the US and that is what most concerns border authorities.