Also look at confirmed seats, sometimes less than ZED. Even if a little more than ZED at least it is a confirmed seat. Last year had confirmed seat purchased 2 days out for $120 from BKK to ICN. Look at r/t ICN to BKK confirmed. Have information ready and if the flight has wifi between AMS and ICN then look on the flight for possible purchase. If prices go up then try and ZED. Go to wikipedia and search IATA XXX (XXX is airport code, here is
BKK) and you can get a fairly up to date list of airlines that fly to that airport and from where. Also remember Bangkok's other airport
DMK.