What time does the airport usually open in the morning, and the plane at 8:00 in the morning

As long as there is a flight at the airport, people at the counter can usually check in 2 hours before boarding. Never seen an airport close

The airport opens early, but the check-in counters are not that early. 6-6:30 or so, but don't worry. Since there are flights, the airport will definitely arrange a suitable time to open.