Flying internationally always requires more planning than domestic travel. If you are intending to fly for an extended period of time in a particular country, then there may be additional requirements depending on the country you are operating in. Below are some general guidelines for flying outside the United States.

Obtain all the permits/permissions required by the country you intend to fly in. Some of the permit/permission processes can take several weeks or more. If you are flying between countries, it is best to use international airports as customs personnel are usually more readily available to clear customs at larger airports.
Be familiar with requirements and use of the Electronic Advance Passenger Information System (eAPIS). eAPIS is a Customs and Border Protection (CBP) Web-based computer application that provides for the collection of electronic traveler manifest information from aircraft departing or entering the United States to or from a foreign country.
Most ICAO states recognize each other’s licenses, but, this does not relieve you of having to provide proof of experience and/or pass a written test to obtain licensing in another country. If you fly an aircraft registered in the United States, you won’t need a foreign license to fly it. Once you’re in a foreign country, you’ll need to understand the procedures specific to that country.
Check the territorial limits of your insurance policy before your trip. Certain insurance policies state that you are covered “in the United States and its territories and possessions, Canada, Mexico, the Bahama Islands, or while enroute between these places. You may have to add additional insurance to cover your particular flight.
Fuel availability may be much different outside the United States and require modification of the aircraft to add ferry tanks. Fuel may be only available to you at particular locations and only at certain times. Cash may be the only accepted method of payment at smaller airports. The distance between refueling stops may be much different than in the United States or fuel may not be available at all at your destination. If you do have your aircraft modified to carry additional fuel, be aware of the performance changes as well as limitations on weight and balance due to the new ferry tanks.
Arrangements and considerations should be made in case maintenance is required during your trip. Just as fuel may not be available or adequate (proper fuel type or quantities), aircraft maintenance my not be available for your aircraft along your route or at the destination. It may also take an extended amount of time to have adequate services delivered to you, not to mention the cost.
Weather reporting may not provide you with adequate information in some areas where weather data is not available or minimal. You may need to find other means to obtain weather if there are no official sources to provide current or forecasted weather.

For More Information:

FAA Safety Briefing – November/December 2012 – Small Airplane, Big World (p. 13):
FAA Air Traffic – International Aviation:
FAA Aircraft Certification – International:
Electronic Advance Passenger Information System (eAPIS):
International Civil Aviation Organization (ICAO):
Aeronautical Information Manual – Chapter 5-1-9, Chapter 7-1-30: