If you are travelling to Frankfurt by plane from Korea, you will arrive at Frankfurt International Airport in Frankfurt am Main. The Korean Air, Lufthasa and Asiana have a direct flight from Seoul to Frankfurt. But if you want to fly from Europe, you can fly directly to Düsseldorf
[ Arrival by plane (Frankfurt International Airportt, Düsseldorf international Airport) ]
To get from Frankfurt International Airport to the city Essen. In Frankfurt airport you can either take the plane to Düsseldorf or take the train to the city Essen. In Düsseldorf Airport you can take the train to the Essen Central Station.