Check-in for international flights: what to know beforehand

Passport, validity and ID card: what you really need

For domestic flights or within the Schengen area, an ID card is almost always sufficient; an international flight leaving that area requires a passport instead, and many airlines ask you to enter the data during online check-in, well in advance of departure. Countries like Egypt, Thailand, India and Russia require a residual validity of at least six months from the date of entry, while others, like South Korea and New Zealand, stop at three; the United States is an important exception, because at American border controls a still-valid passport is enough, with no residual margin required.

If you have dual citizenship you should choose carefully which passport to use for check-in: some countries require entry to take place with the document of local nationality, if held, and presenting yourself with the other passport can create complications at border control once you land, even if boarding created no problem.

Visas, electronic travel authorizations and advance passenger screening

Many non-European countries require a visa or electronic travel authorization obtained before departure, and airlines are required to verify its possession before authorizing boarding, as they risk penalties if they transport a passenger lacking the documents required by the destination country: for the United States, for example, it means an ESTA already approved at check-in time. The advance passenger information system then transmits passport data to border authorities already during check-in: if they don't match exactly with those on the document, boarding can be blocked until manual correction.

Verify that the name entered in the visa or authorization request matches letter for letter the one on your passport, without abbreviations, to prevent the system from flagging a non-existent discrepancy. For anyone with doubts about a country with complex document requirements, verifying tourist visa requirements from the official source, such as the competent embassy or consulate, remains safer than relying only on generic guidance provided during online check-in.

Check-in times and airport presentation

Online check-in opening windows vary more based on the type of document control required than on the simple flight distance: ITA Airways, for example, opens check-in 48 hours before for domestic and Schengen flights, but only 24 hours before for routes to the United States and Canada, precisely because ESTA, visa or green card checks require verification closer to departure. On these routes, moreover, you need to present yourself at the desk for document control about 3.5 hours in advance, a wider margin than the 2-3 hours generally sufficient for an intercontinental flight with simpler documentation.

Customs, minors and additional documents

Some countries also require the completion of customs declaration forms, partially digitized through official apps to download and configure a few days in advance, not while already queuing at passport control. Anyone traveling with a minor to countries that require additional documentation for expatriation must obtain an authorization signed by the non-accompanying parent, preferably in an original paper copy, because some border authorities don't accept a digital scan.

Check your passport validity and visa or electronic authorization requirements at least two weeks before departure, not during check-in: any corrections to your name or documentation require bureaucratic processing that runs out quickly in the days before your flight.