Spectral Procession

So this is a little more than you asked for, but ...

I think for the sake of your mana curve, you want to replace your Sky Spirits with 4* a 1 CMC creature.
Doomed Traveler is probably your best bet as it survives remove spells and can trade with small creatures to remove chump blocks.
Other options include Skywatcher Adept would give you some mana sink against a bad draw, or you can use Zealous Guardian if you DESPERATELY want everything to be WU (I don't think this is a good idea!).

Also:
Wall of Denial really has no place in a deck which wants to win fast.
I'm also not sure about Search Warrent, though the information it gives you is useful.  You're certainly never going to want more than one of these in your hand, so I'd drop it down to one if you want to keep it.
Azorius charm is nice, and has flexibility, but it's a bit situational.
Given both the above, I'd add in a couple of detention spheres.  Not as fast as the charm, but they are one of the best remove spells in existence and will get rid of any thragtusks in your way.
I'd also drop a Favourable Winds and a Steel of the Godhead in favour of another detention sphere, can't see many situations where a game would last long enough that you to have time to cast them if you ended up with 2 of each in your hand (I LOVE Steel of the Godhaed in this deck, but at CMC 3 I'd want to be casting creatures or removing blockers)
Sejiri Refuge is also a choice I have a problem with, the one life means nothing, and the loss of tempo is bad if you draw it early.  Replace it with Hallowed Fountain (this is admitedly an expensive change!)

So, suggested changes:
    -2 Wall of Denial
    +4 Doomed Traveller

    -1 Search Warrent
    -1 Azorius Charm
    -1 Favourable Winds
    -1 Steel of the God Head
    +4 Detention Sphere

    -2  Sejiri Refuge
    -1 Island
    -1 Plains
    +4 Hallowed Fountain

 
I think this is a really really good deck btw, evasive and agro.
It's really important to have a sideboard though, you need to think about what you can do when your opponent responds to your deck!

4 Hindering Light

Detention Sphere if you've got some cash to spend.

Also Geist of Saint Traft is 100%

Squadron Hawk

Ancient Ziggurat - I wouldn't play this in a two colour deck.

Sejiri Refuge - I'd rather have an untapped land than 1 life.

Oblivion Ring is one I'd put in, maybe instead of Search Warrant.

You have entreat the angels, they're flyers, I'd put it in.

Also something like Mizzium Skin.