I think I had the same problem. I typed in the airport code and hit enter thinking the website was smart enough to put in the rest. Instead I got a message saying to pick a destination. So I tried the airport code again and a drop down box appeared while typing the code with the actual city name, so I clicked on the city name and continued. For me it was kind of irritating that an airport code was not enough, that I had to actually pick the city name. I know the Midwest site was a bit more intuitive. I suppose there is a legitimate reason for this, like people picking the wrong airport code and booking it.