For a flight in 2026, the essential documents depend on your destination, but you should always start with a valid Passport (with at least 6 months validity for international trips) or a REAL ID-compliant driver's license for U.S. domestic travel. Beyond identification, you should carry your boarding pass (digital or printed), any required Visas or Electronic Travel Authorizations (like ESTA or ETA), and proof of onward travel if required by customs. In 2026, many countries also utilize digital health declarations or "QR-code" entry forms (like the old ArriveCAN or similar systems) that should be completed 72 hours before departure. It is also highly recommended to bring a copy of your travel insurance policy and a list of emergency contacts. While digital copies on your phone are convenient, having a physical "travel folder" with paper backups can be a lifesaver if your phone battery dies or you lose internet access at a foreign immigration kiosk.