Function

• The identity documents are entered into computer systems where the travelers' names, citizenships and ages are registered and then cross-checked against previous visits, their purpose and any violations. They are also checked against terrorism suspect lists.
  
  

Considerations

• Airlines check for these documents prior to travel. A passenger will not be given a boarding card if the documents are not in order.
  
  

Passport

• The basic requirement for all international air travel is the passport issued by the traveler's country of citizenship. Make sure it has not expired and is valid for the entire trip. It is recommended that the passport be valid for at least six months.
  
  

Children/Canada-Mexico Travel

• For international travel from the United States, all travelers, including infants, must have a passport. Recent law changes require passports to enter any country, including Canada and Mexico.
  
  

Visa

• Some countries require an additional document called a visa, issued by the country to be visited. The document is entered in the passport and entitles the traveler to enter the country. Visas are issued via a consular office prior to travel, and may indicate the purpose of travel.