You have a solid start to a deck, but you're not getting much value off of the creatures you have. Most of them don't have a text box past Flying, and some of them can't benefit from Thunderclap's cost reducing ability. There's a slew of flying creatures that can give you effects that are just begging to be added.
To make space for some of these, I'd start with your vanilla flyers and ones that don't benefit from Wyvern's cost reduction.
As far as your spells go, you could swap some of your auras that grant evasion for more Pacifism style removal effects. Your creatures all have evasion already in the form of flying, and thanks to your general should be larger than your opponent's flyers.
Despite having just been printed at Uncommon, Stone Quarry and Woodland Stream are now commons in the new Planeswalker decks, giving Pauper EDH extra dual lands in those two colors alone.
Oversold Cemetery is great when you're dropping creatures in the yard every turn, and there's plenty of other cards that help you with the top of your deck
The biggest issue with Cifka's list is that Nephalia Drownyard is rotating and it's the only win-con in the deck.
Looking in the block forums might help you quite a bit, you could base your deck on an established one there, then add M14 cards as you see fit. UWr and UWb control is much worse without Sphinx's Revelation, but you could try swapping in Opportunity. Grixis control gets around the need for Sphinx Rev, but Ral Zarek makes the deck a bit pricey.
Aspiring Aeronaut comes with a second flying body
Aven Cloudchaser / Cloudchaser Eagle / Cloudchaser Kestrel / Kithkin Spellduster / Wispmare will handle opposing enchantments
Aven Riftwatcher / Seraph of Dawn can provide life gain
Cephalid Scout / Mulldrifter / Gryff Vanguard / Soratami Cloudskater can all provide card draw in their own ways
Custodi Squire / Griffin Dreamfinder / Sanctum Gargoyle are recursion
Dawnfeather Eagle makes for a good alpha strike, as does Dawnglare Invoker
Expedition Raptor will help you beef the troops even more
Mist Raven / Thornwind Faeries will help as removal
Kor Skyfisher / Silver Drake / Wormfang Drake can reuse some of these newly-added abilities
Warden of Evos Isle can act as your backup general, or with your general to make your army of flying death-machines dirt cheap.
To make space for some of these, I'd start with your vanilla flyers and ones that don't benefit from Wyvern's cost reduction.
As far as your spells go, you could swap some of your auras that grant evasion for more Pacifism style removal effects. Your creatures all have evasion already in the form of flying, and thanks to your general should be larger than your opponent's flyers.
T1 cast Enduring Ideal, grabbing Paradox Haze.
T2 search up Energy Field and Wheel of Sun and Moon to protect yourself.
T3 search up Form of the Dragon and Second Chance. EOT your life total becomes 5.
Next turn, Chance triggers and wheel puts it back into your library to search out again. Ping 5 with Form, rinse and repeat until dead.
All get around #3. Sac outlets really vary depending on what your overall strategy is with the deck, but you've got Ashnod's Altar, Phyrexian Altar, Attrition, Goblin Bombardment, or Dispersing Orb.
Looking in the block forums might help you quite a bit, you could base your deck on an established one there, then add M14 cards as you see fit. UWr and UWb control is much worse without Sphinx's Revelation, but you could try swapping in Opportunity. Grixis control gets around the need for Sphinx Rev, but Ral Zarek makes the deck a bit pricey.
EDIT: Or Master Biomancer. Derped on that one earlier.