According to DFW's website, as well as Korean Air, DFW service to ICN is now being run by the 777-200 of KE, instead of the 744. I guess the demand wasn't large enough for a 744? Seems hard to believe since DFW and ATL are both Delta hubs.
"Bangkok Tower, United 890 Heavy. Bangkok Tower, United 890 Heavy.....Okay, fine, we'll just turn 190 and Visual Our Way
DL does not yet codeshare with KE even though they are part of Skyteam. Hopefully, this will change soon. I have always wanted to see the Far East. Safety issues caused the codeshare to be lifted a couple of years ago, but it appears that DL is planning on reinstating it in the near future.