Originally Posted by
tentseller
If that is the case, the plan won't work. You can only check in 3/4 hours before the flight and you need your BP and exit immigration to go airside to sleep at the transit hotel.
It depends. If it's a USA carrier, including for example SIN-NRT on DL, you can't get through passport control to airside until check in for your flight opens--even if you do OLCI and do not check a bag--until the check in for your flight opens, at most about three hours before your scheduled departure time.
However, if you are flying SQ (I've checked in the evening before for departures to the USA through FRA, so not nonstop), you can check in up to 48 hours before the flight, although the SQ FC check in lounge and special passport control closes in the middle of the night.