There is no airport in Nafpaktos. The closest airport to Nafpaktos is the airport of Patra-Araxos. This small airport works only in summer and receives few charter flights from abroad. From Patra, there are daily buses to Nafpaktos.
Alternatively, you can arrive at the International Airport of Athens that receives many flights from all over the world. From Athens, you can go to Nafpaktos by bus that departs from Kifissos Bus Station. The bus trip from Athens to Nafpaktos is 3 hours.