Why Airlines Sometimes Require Airport Check-In

Online check-in is designed for straightforward reservations the airline can approve automatically. If the system cannot verify part of your trip, it may withhold your boarding pass until an employee reviews it. The message may say “check in at airport,” “see an agent,” or simply that online check-in is unavailable.

One of the most common reasons is document verification, especially for international travel. The airline is responsible for confirming that you have the passport, visa, residency document, or other authorization required to enter your destination. Although some carriers allow travelers to upload these documents digitally, you may still need to present them at the airport if the system cannot verify them. United Airlines, for example, explains that international travelers may need to scan their passports at an airport kiosk unless they have already completed digital verification.

You may also be checking in through the wrong airline. A flight can be sold under one airline’s flight number but operated by a partner airline. In that situation, you generally need to check in with the airline operating the first flight. Look for the words “operated by” in your reservation to identify the correct carrier. American Airlines lists a first flight operated by another airline as one reason its passengers may be unable to check in through the app.

Certain reservations require help from an airport employee. Depending on the airline, this can include passengers traveling with pets, firearms, unaccompanied minors, infants, special assistance requests, or documents that must be inspected in person. American Airlines, for example, requires children using its unaccompanied-minor service to check in with an agent rather than online.

Sometimes the problem is with the reservation itself. A misspelled name, missing birth date, incomplete passport information, recent schedule change, ticket that was reserved but not properly issued, or mismatch between the reservation and your identification can prevent automatic check-in. An airline employee may need to correct or confirm the information before giving you a boarding pass.

The explanation may also be much simpler: you are outside the airline’s check-in window, the app is temporarily malfunctioning, or the website is having trouble retrieving your trip. Before assuming something is wrong with your ticket, try the airline’s website instead of its app, confirm that you are using the operating carrier, and make sure the check-in window has opened.