Online check-in is the service that the traveler who purchased the flight ticket can pass the ticket control and select their seat before heading off to the airport for their flight. Some airlines offer online check-in at no additional cost, while some require extra charge for seat selection.
Online check-in are generally available on airlines website.
There may be differences in the time each airline company open their check-in service. Typically this period is between 48 hours and 12 hours before flight.
When you check-in online, the time you should to be at the airport changes by the airlines. You will be informed on this by the airline during your online check-in.
Below, you can sign in to the online check-in site of the airline you are flying by and you can perform your check-in process.
For online check-in you will be using your PNR number, which is sent to you by sms and / or email when you reserved your ticket.