Yes, you can change a date of birth on a flight booking, but you cannot do it online through most airline websites. Because the date of birth is a critical security detail linked to TSA Secure Flight or international API (Advanced Passenger Information), you must usually call the airline's customer service or contact them via their official chat/email. If the error was a simple typo (e.g., entering 1985 instead of 1986), most airlines will correct it for free or a small administrative fee, though they may ask you to email a photo of your passport or birth certificate to verify the change. It is vital to correct this before you arrive at the airport, as a mismatch between your ticket and your government ID can result in being denied boarding or held up at security checkpoints.