What is Argo II?

The Argo II is a flying ship that Leo Valdez created for the mission. It is technological genius and provides for their every need, even some needs that they don't know they have. It's guidance system is a mechanical dragon named, Festus. This is what Leo rides to Calypso's island at the novel's end. This is also the ship that starts the war between Camp Jupiter and Half-blood when Leo is possessed by spirits and fires on the Roman camp.