At Intermediate Airports
Unless you are taking a long direct flight, there will most likely be international stops en route to the U.S. Your flight will stop in Europe (sometimes in the Middle East, depending on the airline) if you are traveling the Atlantic route, or in Asia if you are traveling the Pacific route.

Chart of Airline Transit Locations

Before approaching the stopover, you will hear announcements for various things like local time, weather, and information about your onward journey. Listen to these instructions carefully, as the final destination may differ for different people. Information about the departure gate number, terminal number, etc., may be available on the TV screen, as well. The terminal and gate number information may also be printed on your boarding pass.

At the international stopover, you are generally required to exit the aircraft, irrespective of whether you will be boarding the same aircraft again. While deplaning, you must carry all your personal belongings with you for security reasons. Even if you are boarding the same aircraft again, it will be emptied completely for cleaning, refueling, and stocking supplies.

In some cases, you are allowed to remain in the aircraft.

The stopover usually lasts a few hours.

Once you are inside the airport, you can move around freely. If you wish, you may buy some food or drink. However, you may not be hungry, as you may have eaten in the airplane. You will also receive food in the next flight. You may want to freshen up in the restrooms located in the airport. Shower facilities are generally not provided at the airport.

It's always advisable to keep your watch in sync with the current time zone.

Duty-Free Shopping
There are typically many duty-free shops around the airport. You may purchase many items duty free, such as liquor, perfumes, cigarettes, chocolates, etc. You can buy these items as gifts for your U.S. contacts, within your duty-free allowance.

Changing Flights
As most airports are very large, locating your flight's designated gate might take some time. Keep your next flight in mind as you plan your activity. Search for your next flight's terminal and gate number. Airports normally have good directions/maps. You can also ask airport staff for directions to the gate. Once you locate the gate, you may spend your remaining time looking around.

Try to be at the departure gate at least 45 minutes before your departure time. Your hand-baggage will be x-rayed again, and you will have to pass through a metal detector.

Keep an eye on the TV display screens, as it is possible that your gate might change at the last moment.