Procedures up to Boarding There are 2 types of boarding methods with AIRDO. Online check-in Online check-in is available from 24 hours prior to departure.Passengers who have completed online check-in can proceed directly to the security inspection. Airport Boarding Procedure This method entails completing boarding procedures at the airport counter or self service check-in machines, and then proceeding to the security inspection. Waiting for Seats on Full Flights Flight Connections