3. Pchan3's Mods
If flying around Minecraft in your very own steam powered airship sounds like your idea of a good time then Pchan3's Mods are the mods for you. Adding a number of steam powered contraptions including a boat and an airship this mod allows any aspiring steam-punk pilot to take to the skies and seas, doing battle with the new sky-pirate mobs and allowing you to zip effortlessly from one of your floating steam fortress to another (You'll have to build them yourself though). The mod also populates the world with new highwaymen mobs who are all too willing to rob you of your hard earned gold before shooting you in the back. Of course you don't have to pay them to leave you be, you can go all vigilante on these reprobates, netting you a swish new gun if you successfully take them down. You can grab these mods
here