There is quite a wide selection of vehicles for traversing Final Fantasy II. Here is a list of your choices.

Chocobo Chocobo's make their series debut in Final Fantasy II. They are able to go anywhere the party can go, but without random enemy encounters.

Canoe With the canoe, you can travel across lakes and rivers.

Ship The ship can take you across the vast oceans. It can dock at harbors, and along any shore. With the canoe in your possession, it can dock at river outlets.

Snow Craft The Snow Craft is used to cross the snowy plains of the northern areas.

Airship With this vessel, there is nowhere you cannot go. However, you can only land in the grassy plains.