Skycat Sovereign

Flying
Skycat Sovereign gets +1/+1 for each other creature you control with flying.
{2}{W}{U}: Create a 1/1 white Cat Bird creature token with flying.

Windreaver

Flying
{W}: Windreaver gains vigilance until end of turn.
{W}: Windreaver gets +0/+1 until end of turn.
{U}: Switch Windreaver's power and toughness until end of turn.
{U}: Return Windreaver to its owner's hand.

Pride of the Clouds

Flying
Pride of the Clouds gets +1/+1 for each other creature on the battlefield with flying.
Forecast — {2}{W}{U}, Reveal Pride of the Clouds from your hand: Create a 1/1 white and blue Bird creature token with flying. (Activate only during your upkeep and only once each turn.)