Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Redmond to Bucharest as you normally would.
Bend/Redmond (RDM) is the airport you will fly out of if you book a flight from Redmond to Bucharest. You should not have trouble finding flights to Bucharest from Bend/Redmond; the airport handles an average of 0 outbound flights to Bucharest per day. You should also have plenty of airline options to choose from since 0 airlines have flights from the Redmond airport to Bucharest. It is only a 1.8 mi journey to Bend/Redmond (RDM) from Redmond’s city center.
These are just IATA (International Air Transport Association) codes. They are used in aviation to identify and differentiate airports. That’s why a Bend/Redmond Airport to Bucharest Otopeni Intl Airport flight would often be abbreviated as a RDM to OTP flight. While you’re still figuring out your travel plans, it’s not a bad idea to learn the names and codes of other airports around these areas: Bucharest Baneasa Airport (BBU).