Is it possible to pay for a flight from Nigeria to Oakland international airport CALIFORNIA???
Is the flight supposed to be for someone you “ met “ on-line , who has “ fallen in love “ with you, and who you have perhaps already sent money to? By Western Union or another similar untraceable and irretrievable payment method?
Has he asked you to send him money for a ticket to the USA?
If so, please read the information about scams in this link to the US Embassy in Nigeria website, especially the section about dating/ romance scams.
If any of the factors I have mentioned are familiar, then you are being scammed.