We have been flying Norwegian Air Shuttle since they came into the retail market--to and from Europe. Norwegian's process were half or one third the price of the big legacy carriers, and they have been the saving grace to us travelers that fly to Europe often.
We need someone like Norwegian to keep the "big boys" prices in check and fair. But for now, look for some great airfares to the places Norwegian flies. Competition will be trying to put a nail or two into Norwegian's coffin.
We caught a 2 hour sale a few weeks ago with a British Airways non-stop flight to LHR and on to Berlin for about $436 roundtrip. And my wife jumped on that one. That'll be my second and my wife's third European trip in the last year.
If Norwegian doesn't make it, it's been awfully nice. I just hope other budget airlines fill in the space in the market.