I travelled to the USA for the first time in many years recently. It was quite a job !
Firstly you must have either a Visa in your passport (which I had) or an ESTA temporary visa which can be obtained on the internet.
I was flying into Philadelphia then traveling on to Jacksonville. All travellers to the US when changing planes before a final destination have to claim their baggage before proceeding to the next plane.
No one told me this when I checked in! Also I can’t remember any announcement on the plane about this.
Once you leave the plane you will have a big wait to pass through US border control. At Philadelphia there were a dozen desks but it takes five minutes to process each person as they have to check your finger prints and do a retina scan. It took me about 25 mins to pass through immigration and I was near the front of the queue.
You then pick up your bag and go through US customs. Just round the corner from customs is a big shute where the cases are slid down to be taken to your next flight. That part was well organised and my case made the connecting flight OK.
Next it was quite a long walk to the inevitable security which was a slow process. Then a long walk to the flight to Jacksonville.
Boarding was finished by the time I arrived at the gate and everyone was sat down on their seats ready for the plane to leave. Really….. Too close for comfort for me !
So when you book flights to the USA make sure you have an absolute minimum of two hours to make your connection.