Advance Passenger Information System

Advance Passenger Information System or APIS is an electronic data interchange system established by the U.S. Customs and Border Protection (CBP), 
APIS governs the provision of a limited number of data elements (identification details from the passport and basic flight information) from commercial airline and vessel operators to the computer system of the destination state. Required information should conform to specifications for UN/EDIFACT Passenger List Message (PAXLST) formats.
Beginning in May 2009, private aircraft pilots must also provide the necessary information to the CBP. The regulations were put into effect in December 2008 with a 180-day voluntary compliance period.
eAPIS (electronic APIS) is a public website which allows small commercial carriers to transmit data to the CBP electronically.
When travelling to or from certain countries, passengers are required to provide advance passenger information (API) before they check in or they will be unable to fly. These countries include
and some more
The required information consists of: