Every form a traveler may need for airport travel, in one place. Every link below goes to the official government or airline page, never to a third-party form reseller.
Scam warning: only use official .gov links for ESTA, UK ETA, and ETIAS. Third-party sites copy the official forms, charge inflated fees, and sometimes never submit anything. The official US ESTA fee is $40.62 at esta.cbp.dhs.gov. The official UK ETA fee is £20 at gov.uk/eta. ETIAS is not in operation yet, so any site charging for it today is not official. If a site charges more than the official fee, close it.
Fees and requirements change. Confirm every fee and requirement at the official source before you pay or travel. Where an official source publishes no fee, the card says “fee not published”.