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.

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.

Healer's Hawk

Island

Favorable Winds

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

Gravitational Shift

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

Rally of Wings

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

Glacial Fortress

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

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.)

Lyev Skyknight

Flying
When Lyev Skyknight 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

Winged Words

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

Empyrean Eagle

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

Judge's Familiar

Flying
Sacrifice Judge's Familiar: Counter target instant or sorcery spell unless its controller pays {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.

Spectral Sailor

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