Originally Posted by
vanillabean
Say you’re a Danish/American dual citizen and you have a reservation HND-HEL-LAX with a stopover in the EU HEL during which you separately fly to CPH and back. Would the reservation include my US passport only? Or say NRT-CPH-SFO to make it more EB-compliant?
Just have the US passport on the HND HEL LAX booking. Use your Danish passport to enter and exit Schengen, if the lines are shorter. There is no passport or advance passenger information needed on the HEL CPH HEL booking.