They are now actually one of the largest airlines in Europe.
By some metrics (including passengers flown), they're THE largest airline in Europe - even when you consider AF/KL, IAG (BA, Iberia, Aer Lingus and subs) and Lufthansa's group as being single airlines, which they aren't.
Frankly I wish that we had airlines like this. I just looked up a flight from London to Barcelona. $28 one way for a 2 hour 15 minute flight. Considering the length of most of their flights, this seems reasonable. It's less about the bathroom income and more about being able to eliminate bathrooms through decreased demand and putting in a couple more seats.
I wish I could fly to to cities within 2.5 hours for <$100 roundtrip.
They don't do this kind of promotion any more, but when I lived in England I once flew to Belfast for the weekend for 2 pence. The promotion covered even the taxes, and I had the right kind of debit card to avoid the card charge. And we sorta do: Spirit is pretty close to the Ryanair model, but they just aren't as cheap.
