Transportation is key to easy movement in Monster Breeder. If you were walk from each city and town to the next, why, your feet would surely rot off. Thankfully, the people of Aerra have ways to get you from point A to point B, very easily.
Zeppelins are giant air-boat sorta things designed to carry you in the air at great speeds. To get to a city, you must first know its route. Can't exactly pilot a zeppelin if you don't know where you're going, can you? Well regardless, it's a small fee to take you where you need to go, and is quite convenient.
Trains transport you from place to place. You don't need to have visited the city/town to go there, but the downside is that it is expensive, and upon leaving the city/town, you may face some very powerful monsters. Be sure to take trains only when absolutely necessary.
Boats are a way to get through the seas of Aerra. They act as trains, just for water instead.
From Sunday 5PM - 10PM AST (aerran standard time) is Happy Train Time, in which all train rides are free. The same is true for all boats on Wednesdays at the same time.