Air Busan's official FAQ instructs passengers with infants or children on domestic routes to bring a document proving the child's date of birth, such as a resident registration extract, family relationship certificate, health insurance card or passport. Adults need recognized photo identification such as a national ID or driver's license; any mobile ID must meet the airport's accepted-document requirements. Even with electronic tickets, boarding passes and identity documents are needed for the airport security and boarding process. Check the current counter and check-in deadlines for the flight, and carry separate evidence if claiming a qualifying discounted fare.