This is the big one people talk about when discussing Engineering. How much fat cash you can make selling the quadrillion mounts you can make with Engineering. There's 7 different mounts you can make, but a single engineer can only really make up to 5.
HimmelsgolemThis is made by making
Jards merkwürdige Energiequelle every day for a month then combing it with 30
Lebendiger Stahl. This is probably the most common one people make who have engineering and don't do a lot of old world stuff. It's pretty straightforward and doesn't require too much effort to be profitable. You will need to go out and kill MoP stuff to get the recipe to make this. If you're only going to be making this one with your old world crafts you would probably benefit from having alchemy over mining because you'll save a lot of gold my making your own living steel. Still a pretty reliable profit because it's time gated, there shouldn't be too much competition on it, so don't be in too much of a rush to sell these because you have 30 days to move it before you make a second one. I'll often sit on mine for a couple weeks if the price dips too low and wait until I can get an extra 5-10k out of it. There's a popular speculation that these will go up in price after the next expansion like at the beginning of legion as people will want them to farm herbs, so if you want to potentially get more from them you could save up your Jard's.
Rakete mit abgereichertem Kyparium and
Geosynchroner WeltendreherThese mounts are really expensive to make and really slow sellers too. The cost of the 3
Kugel der Geheimnisse is going to be more than double what it takes to get everything else combined, and eating up 60k raw gold for weeks at a time isn't always good, so don't make these if you can't afford to spare the gold for a while. You can only make one of these mounts per engineer depending on whether you go Goblin or Gnomish Engineering. Which specialisation you want to go with will depend on which mount is more profitable and which one has more competition. Choosing the one that is currently more profitable isn't always best, you might want to watch the market on both for a while before choosing and see which one is better to make on your realm. Once you have a second engineer you can start making both mounts, which is a good reason to consider doubling up along with extra Jard's cooldowns.
Chopper des Robogenieurs /
FeuerstuhlThis one is my best seller for engineering mounts. Which one you make will depend on whether you're Horde or Alliance, but they're pretty much the same, and which one you make just depends on your faction. Note that you need to be horde to use the hog and alliance to use the chopper, so if you're on a realm with a heavy faction imbalance you might have a hard time selling the less popular faction one on the AH. This is a pretty good use of Titansteel, which is a great shuffle to do by itself so it's real profitable if you do that. One thing to keep track of is how much Arctic fur you have, it's usually a pretty inconsequential component in terms of cost, but be sure to stock up on a bunch when you have the opportunity, I've been caught out a few times where I needed to make a chopper and there were either none on the AH or they were listed for an obscene price. If you run out you can also check the leather trader in old dalaran who can trade you 1 for 10 Heavy Borean Leather, quite expensive but it's at least better than not making a chopper at all.
I also like to stock up on multiples of the vendor mats for these at a time because it's fairly cheap and saves the trip going to
Keech der Große (Goblin in Vale who sells mats for these and other crafted mounts) every other day. TSM Vendoring or similar macros/addons help here because buying up 40
Goblinmaschinenkolben takes forever to do manually, if you're also making the other engineering mounts or panthers/Vials (everything except
Pyriumbeschichtete Kristallphiole for VotS) then you can pick up the vendor mats for those too when you visit him.
Flugmaschine and
Turbogetriebene FlugmaschineThese 2 are engineering only mounts, which means you have to have engineering to fly them and also to learn them. People generally assume that nobody would buy these because if you have engineering you'd just make them yourself, but these do actually sell on occasion, albeit slowly probably to engineers who are too lazy to make it themselves. The Flying Machine is a very cheap mount, so people often buy it because spending 1-5k to +1 a mount count is easier then going to get all the mats for it. Because it's so cheap it can be a great mount in terms of margins, but is sometimes subject to people crashing the price on them to barley anything, so if you don't like markets where people do that then I'd avoid this one.
Turbo-Charges is a lot more expensive to make, so is more like a traditional mount market where it costs thousands of gold to make and you sell it for a decent profit. These are good to sell if you pay attention to the
Khoriumbarren market and can smelt
Teufelsstahlbarren. As long as you don't pay too much for the mats it's quite profitable. Don't fall into the trap of buying the
Hula-Wackelpuppe off the AH, it's 100g (or less with rep) from a vendor in Shattrath.