UA: IAH⇄SIN $881 ai RT 4.3-4.5 cpm (19940+ miles)
UA, Depart May.2 or 3. no stay requirement.
I just booked:
IAH-NRT-SIN on May 3rd. Arrive SIN at 1am on May 5.
Then return SIN-NRT-IAH at 5am .
Question: what is the custom process at midnight at SIN?