Check your reservation for possible flight changes. The airline slashed nearly 1,000 flights from its July schedule over the weekend to give it more breathing room as the travel surge and other ...

Check your reservation on the airline's website to see if there are any changes. If the flight is in the immediate future, check the flight status feature on the airline's website.

Download your airline's app ahead of time, make sure your reservation details are in, and then use it to check in. That way, you can head straight to security when you arrive at the airport.

Also, to be on the safe side, enter your passport information with both airlines. Your Delta reservation code should be listed on your Korean Air e-ticket.

Starting June 3, 2025, United Airlines will require passengers to check in for domestic flights at least 45 minutes before departure, replacing its previous 30-minute guideline.