How does checking in online for a flight work?

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Tags

1. #security
2. #departure
3. #check
4. #boarding
5. #screen
6. #hours
7. #before
8. #display
9. #barcode
10. #checkpoint
11. #scheduled
12. #office
13. #flight
14. #starting
15. #device
16. #print
17. #available
18. #online