section_path: Regulation of internal borders/Air travel
section_name: Air travel
paragraph_text: Air travel
  
  For flights within the Schengen Area (either between Schengen member states or within the same Schengen member state), law enforcement agencies, airport authorities and air carriers are permitted only to carry out security checks on passengers and may not carry out border checks. Such security checks can be conducted through the verification of the passenger's passport or national identity card: such a practice must be used only to verify the passenger's identity (for commercial or transport security reasons) and not his or her immigration status. For this reason, law enforcement agencies, airport authorities and air carriers cannot require air passengers flying within the Schengen Area who are third-country nationals to prove the legality of their stay by showing a valid visa or residence permit. In addition, according to European Commission guidelines, identity checks on air passengers flying within the Schengen Area should take place only either at check-in, or upon entry to the secured zone of the airport, or at the boarding gate: passengers should not be required to undergo a verification of their identity on more than one occasion before their flight within the Schengen Area. Notwithstanding those principles, the identity checks function as practical border controls and they affect illegal immigrants who arrive in Greece (which until 2024 had no land border to another Schengen country, although those land border controls can be reestablished if needed) and want to fly to some other Schengen country. The requirements as to which identity document to possess varies by country and airline. Normally a passport or EU national identity card is needed.
  
  Travellers boarding flights between Schengen countries, but originating from a third country outside the area, are required to go through Schengen entry border checks upon arrival in the Schengen Area. This is because the route originates outside the Schengen Area and the authorities at the final destination would have no way of differentiating between arriving passengers who boarded at the origin and those who joined in the middle. Additionally, travellers are required to process through Schengen exit border checks upon departure.