Skycat Sovereign

Flying
This creature 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.

Glacial Fortress

This land enters tapped unless you control a Plains or an Island.
{T}: Add {W} or {U}.

Rally of Wings

Untap all creatures you control. Creatures you control with flying get +2/+2 until end of turn.

Winged Words

This spell costs {1} less to cast if you control a creature with flying.
Draw two cards.

Favorable Winds

Creatures you control with flying get +1/+1.

Geist of Saint Traft

Hexproof (This creature can't be the target of spells or abilities your opponents control.)
Whenever Geist of Saint Traft attacks, create a 4/4 white Angel creature token with flying that's tapped and attacking. Exile that token at end of combat.

Judge's Familiar

Flying
Sacrifice this creature: Counter target instant or sorcery spell unless its controller pays {1}.

Lyev Skyknight

Flying
When this creature enters, detain target nonland permanent an opponent controls. (Until your next turn, that permanent can't attack or block and its activated abilities can't be activated.)

Plains

Gravitational Shift

Creatures with flying get +2/+0.
Creatures without flying get -2/-0.

Island

Empyrean Eagle

Flying
Other creatures you control with flying get +1/+1.

Thunderclap Wyvern

Flash (You may cast this spell any time you could cast an instant.)
Flying
Other creatures you control with flying get +1/+1.

Healer's Hawk

Flying
Lifelink (Damage dealt by this creature also causes you to gain that much life.)

Spectral Sailor

Flash (You may cast this spell any time you could cast an instant.)
Flying
{3}{U}: Draw a card.

Pride of the Clouds

Flying
This creature gets +1/+1 for each other creature on the battlefield with flying.
Forecast — {2}{W}{U}, Reveal this creature 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.)