The first thing I would recommend is Smuggler's Copter over Mizzium Tank .

Hmm any reason for the Copter other than the hand filtering? Is the evasion with flying more important? I already have the discard and draw on Sarkhan's +1 ability and Mizzium Tank can become a 4/4 trampler just by casting a spell (in case I get board wiped and don't have a Silumgar's Scorn ready or don't have an extra creature to crew it or something). I can try adding it and testing to see if the extra draws help any (I may have just been getting lucky with TappedOut's playtest engine).

Filtering, evasion, less mana. It’s the best vehicle they’ve printed imo, it’s been banned in multiple formats.

Also I think Lightning Bolt would be better than Draconic Roar . Unless you want the Roar for flavor reasons, I’ve been known to do that myself.

What’s the fling for in the sideboard? I think it would be better suited as Aether Gust or Mystical Dispute .

True about the evasion the more I think about it. I mean I've got fliers already but wouldn't hurt to have more. I did playtest with it and the extra filtering helped with getting lands I needed, but honestly I could solve that problem with the fetches (something I've been holding off on due to the price). One thing that I can do with Mizzium tank that I can't with the copter though is really pump it up since its effect is a pseudo-prowess like Sprite Dragon's is. The fact it has trample already makes the pump viable and I can also turn it into a 4/4 flier with its pump still active with Dance of the Skywise if that's the last spell I target it with.

You mentioning more counter spells got me thinking though. I could always toss more spell pierces in or similar. Fling is for when the opponent wipes the board (which has been happening to me more often lately). It allows me to use the Slumbering Dragons as a burn spell in reaction. They were supposed to be boarded in over the Bioshifts since there's no creatures to move counters to when you're being wiped. You can also attack with an activated Slumbering Dragon then fling it post-combat for the kill shot.

Few more playtests down vs some other decks and when I get any of the synergies going on this deck can kill at turn 5 (1 turn slower than my monored burn decks). It's just getting them reliably and getting the lands I need that seems to be the problems :/. So speed really isn't the issue.

Hey, the flavor is great here and the deck name gave me a laugh :)

I second the Smuggler's Copter suggestion, but I don't think you should cut Tank for it. Consider cutting Dance of the Skywise for Copter? Sarkhan's Whelp seems underwhelming with only 3x Sarkhan. Consider Gadrak, the Crown-Scourge instead? If you add more Vehicles since he has interaction with Vehicles and Treasure tokens from Goldspan. He can block or crew with five power before he can attack.

Consider Blinkmoth Nexus ? It can become a flying artifact creature that can crew Copter or Tank, can also move counters to it with Bio and it's an artifact for Gadrak.

Thank you Hardhitta7 and multimedia for the suggestions!

I went ahead and added 2 copters and 2 blinkmoth lands and then added in 3 scalding tarns just to see how it would play. It actually plays about as fast as my burn decks when I get a good hand now! I'm still not sure where to fit Gadrak in though. I do think he's a good include and I have a few extra copies of him from cracking M21 packs, just not sure what to shake up for it or if I should now.

In modern the 5 cmc dragon threat is really only going to make it you need to have all 4 copies of Sarkhan, Fireblood , he even has the means to reduce the effects of his own redundancy so why not increase the chances you get a 5 cmc dragon out faster?

now your current choice of 5 cmc dragon maybe the new hotness, but what does it really do for your deck synergy wise? Glorybringer and Demanding Dragon both fit the scary dragon top end threat while being removal. Stormbreath Dragon represents a lot of damage and is harder for white decks to remove with path. Terror of the Peaks though is probably the dragon with the most synergy, you get bonus damage from your dragons, though Hunted Dragon does give the opponent some creatures to trigger the slumbering dragon.

Now your sprite really wants free spells or ones that are cheap and cantrip, for consideration Gut Shot and Dismember are both cheap/free removal, Mutagenic Growth also free, these cards also synergize with another suggestion lower down. Manamorphose is probably the most free spell. Opt is just strong cantrip.

Now for possibly the best dragon for this shell that seems to like to target it's own creatures with spells Orvar, the All-Form will get out of hand pretty easily giving all your buff spells a Clone tagged on it.

other considerations are the above mentioned bolts, cheaper spell and doesn't require hoops for it to dome someone. Mutavault is a dragon man land, extra worth considering if you go heavier into a dragon tribal. the full 4 on copter, it is just the best vehicle for it's cmc, well there is the The Omenkeel ... I'd almost suggest having just 4x of these two as your full vehicle detachment the god side would even provide late game options. Spell Pierce is also likely a strong choice over the dragon counterspell, double blue can be tricky to pull off and also have double red.

Nice suggestions, but they would totally break the theme of the deck and how it currently works. You're basically suggesting a Prowess deck with a big dragon finisher. That's not a bad deck, it's just not what this deck is about although it has elements of both of those things.

The choice of Goldspan Dragon for the 5 cmc slot isn't because it's the new hotness it's that it enables all of my spells easily and defends itself by generating 2 mana for use with Roar for spot removal/damage to player or Scorn for protection. In tests the game usually ends the turn after he comes out if I pull it, not because of its power but because of all the other effects going on. Demanding Dragon was the original dragon finisher in this deck before Kaldheim dropped but did not work out well for me in tests since most of the time all it did was remove a zombie token. Glorybringer is a great finisher, but I'm using my copies in another deck and if you exert it you can't use it to crew a vehicle in an emergency (I'm trying to finish as fast as possible so the only combo would be exert and then Fling it afterwards, in my other dragon deck it works much better). Stormbreath Dragon might be a good option if Goldspan didn't already protect itself. Terror of the Peaks is probably the worst synergy with this deck since by the time I'm dropping a 5 cmc dragon the game is over the next turn. The 5 drop has to be relevant the turn it comes out so Goldspan Dragon having Haste and an extremely relevant ability to generate mana to cast removal or protection spells seems to be the best fit for that slot.