The biggest benefit of checking in online is that it fast-tracks your check-in process by helping you skip the waiting lines at the airport. Once you check in online, you have the option to print your boarding pass at home or receive it by email, which you show at the airport gates.  If you’re travelling without checked luggage, you can proceed to the gate directly, and if you’re travelling with luggage, you can head straight to the fast bag drop counter to check in your bags.