Check Ryanair, Easyjet, or one of the other discount airlines. Last time I was over there flights that short were almost as cheap as the trains, sometimes moreso and a HELL OF ALOT shorter. Seriously man, after a couple 6 hour+ train rides through Europe you don't want to see a pair of tracks ever again in your life. It gets fricken old. And they have discount airlines that most americans would rightfully drool over. Make use of them if they have a flight there.
If not, than you're stuck with the train.