Terminal 5 is mostly used by British Airways but the others have no particular airlines using them.
You have to use the Piccadilly Line of London Underground which serves all of Heathrow's Terminals.
American Airlines uses Terminal 3 at Heathrow Airport.
The UK doesn't use ZIP codes, it uses post codes which are much more detailed, so each of the five terminals at Heathrow will have its own post code.
They have to if they want a holiday here in England.
Use the tube (underground) from any terminal.
Yes, we have Heathrow and Gatwick to name a few airports
During a 4-hour layover at London Heathrow Airport, you can explore the shops, restaurants, and lounges in the terminals, take a walk around the airport to stretch your legs, or relax in one of the designated rest areas. You can also use the airport's free Wi-Fi to catch up on work or entertainment, or visit the Heathrow Express train station to take a quick trip into central London for a brief sightseeing excursion. Just be sure to allow enough time to go through security and reach your gate for your connecting flight.
Yes it is but your problem will be parking when you get there. Unless you have made arrangments to park somewhere, don't even think about using a car in Central London. It will be much easier - and faster - to use 'the tube' ie London Underground, even from Heathrow.
19 hours if you use KLM Airlines.
It depends on the airline that you are using. British Airways depart from Terminal 5.
you can take heathrow express from airport to paddington station , then from there you can take a bus to London St pancras station and then train to dover, or you can use a taxi which can be cheaper if you travel with your family.
Delta flies out of Terminal B at Kansas City. I've added the link for the Kansas City airport website - it has a nice list of the airlines and their terminals.