Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Buffalo to Sapporo as you normally would.
Buffalo (BUF), located 8.3 mi from the city center, is the airport you fly out of when you book flights from Buffalo to Sapporo. 0 airlines have flights from Buffalo to Sapporo on a regular basis. Booking flights from Buffalo to Sapporo should not be difficult; the airport handles an average of 0 outbound flights to Sapporo per day.
These are just IATA (International Air Transport Association) codes. They are used in aviation to identify and differentiate airports. That’s why a Buffalo Airport to Sapporo Chitose Airport flight would often be abbreviated as a BUF to CTS flight. Sapporo Okadama Airport (OKD) are some additional IATA codes for airports related to your trip.