I (overseas) airfare

cyberrn (82)in SCT.Crypto.Crypto • 13 hours ago (edited). CyberRN (82)
Why is the airfare to Barcelona lower than I thought while I was booking a flight ticket at Interpark? When I clicked on the Incheon-Barcelona round-trip ticket and compared the airfare, Korean Air and Singapore Airlines had a large price difference. I'm not looking for where to go