When flying from Cebu to Bilbao, the time of day you decide to fly out makes little to no difference towards the overall price you’ll pay on tickets.
Located just 4.9 km from the city center, Bilbao (BIO) is the airport most travelers will use when flying to Bilbao from Cebu.
These are just IATA (International Air Transport Association) codes. They are used in aviation to identify and differentiate airports. That’s why a Cebu City Mactan Intl Airport to Bilbao Airport flight would often be abbreviated as a CEB to BIO flight.