Usually, white-blue decks are thought of as "control" decks: slow and creatureless, and not the beatdown lover's style of choice. But if you like to pound your opponent with hordes of Soldiers, the Celestial Assault deck is right up your alley. It uses some of the cooler abilities from white and blue-flying and combat tricks-to take over the battlefield.
Your flying creatures are hard to block and your Gustcloak creatures let you back out of combat if it doesn't go your way, so you should be able to constantly attack with an indomitable army. Just to make sure things go your way, Celestial Assault is filled with spells to protect your marauders. Blue surprises like Meddle and Mage's Guile make your opponent's tactics backfire. And white cards like Inspirit, Piety Charm, and Akroma's Blessing can each be used to either rev up your offense or bolster your defense.
The beauty of Gustcloak creatures is that sending them into battle is a can't-miss proposition. They give you - not the defender - the final say, so you can attack first and make decisions later. If a Gustcloak creature is unblocked or stopped by a smaller creature, great. If a bigger blocker steps up, pump up your creature (if you have the right spell) or just untap and retreat. Make your opponent call your bluff all day.
To make sure you don't run out of gas, use Airborne Aid and Seaside Haven to draw extra cards. Daru Cavalier and Screaming Seahawk let you seek out their twins when you play them, so they're especially good if you expect a mass elimination spell. Play one while holding the one you searched for in your hand, and you'll bounce back fast if the board is wiped clean.
There are quite a few Onslaught cards that would be excellent additions to this deck. Aven Brigadier is a natural fit since it gives bonuses to all your Birds and Soldiers and comes with a large flying body to boot. Mobilization lets you churn out Soldier tokens and allows most of your creatures to attack without tapping. With Celestial Assault, you have nothing to fear in combat - so go pick some fights!
