EEKS Joe, well spotted I had forgotten all about the 'other' airport.
Yep the ferry crossing is quite expensive, so if on a budget it's best to travel as a foot passenger. No one checks if you have tickets for the aircraft type seats so it's not worth paying the extra! There are showers, also racks are provided for your luggage to save lugging it around with you.
It's a fun and a different start to a holiday in Corfu, perhaps not much cheaper than a direct flight, but for travel out of season it does give us another option.
Eileenx