Everything depends on the airlines, there is a term of 36 hours, to others that for safety reasons, you have to go in person, 5 hours before the departure of the flight.
In the case of Avianca neither the check in was necessary.
For the airline you must perform the.check in
Check in, you mean? It can be done from 2 days and up to 2 hours before the flight. You do it from the airline's website or at the airport there are some self check in machines.
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