Fly on the same passport whose data you entered at booking. Many destinations and airlines require remaining validity after your trip; staff check this before ticketing. A damaged or almost-expired passport can stop you at KBL even if you have a ticket. Names on the ticket must match the passport machine-readable zone as closely as the airline requires (usually exact spelling). If you hold more than one travel document, tell the office which one you will present at each border. Rules change. Confirm visas, transit, and baggage with the airline and the relevant embassy before you travel. Is this legal advice? No. It is how Sharifi Neya frames documents for ticketing. Governments and airlines can impose extra checks the same day.