International layover: what checks to expect

Immigration control depends on the country of transfer, not nationality

Some countries require crossing passport control even just for airside transit; others offer sterile areas where passengers changing flights never encounter a border officer. The United States falls into the first category: every international passenger, even if headed elsewhere, is admitted or denied at a CBP inspection gate before proceeding, and the Transit Without Visa (TWOV) program remains suspended.

Customs and baggage collection during transit

Customs come into play especially when baggage must be collected during transit: in the United States this happens at every first arrival, even with a single ticket and baggage tagged all the way to final destination. In other countries, with a single ticket, baggage remains in the sorting system and the passenger does not see it until final arrival.

Transit visa and customs forms to know in advance

Some countries require a transit visa even for passengers who never intend to leave the airport, a requirement to verify well in advance along with other electronic travel authorizations similar to ESTA. Completion of customs forms, required by some countries even for transit alone, should also be prepared beforehand: having the requested information ready in advance avoids delays precisely when time is most limited.

If the transit is in the United States, verify that you have a valid ESTA or visa even if you will never leave the airport: you must still collect baggage, pass customs and CBP inspection before boarding your next flight.