Lofty Denial

Counter target spell unless its controller pays {1}. If you control a creature with flying, counter that spell unless its controller pays {4} instead.

Plains

Mist Raven

Flying
When Mist Raven enters, return target creature to its owner's hand.

Aerial Assault

Destroy target tapped creature. You gain 1 life for each creature you control with flying.

Dawnfeather Eagle

Flying
When Dawnfeather Eagle enters, creatures you control get +1/+1 and gain vigilance until end of turn.

Pacifism

Enchant creature
Enchanted creature can't attack or block.

Azorius Guildgate

This land enters tapped.
{T}: Add {W} or {U}.

Island

Kangee, Sky Warden

Flying, vigilance
Whenever Kangee, Sky Warden attacks, attacking creatures with flying get +2/+0 until end of turn.
Whenever Kangee blocks, blocking creatures with flying get +0/+2 until end of turn.

War Screecher

Flying
{5}{W}, {T}: Other creatures you control get +1/+1 until end of turn.

Watcher of the Spheres

Flying
Creature spells with flying you cast cost {1} less to cast.
Whenever another creature you control with flying enters, Watcher of the Spheres gets +1/+1 until end of turn.

Talon Trooper

Aven of Enduring Hope

Flying
When Aven of Enduring Hope enters, you gain 3 life.

Winged Words

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

Revoke Existence

Azorius Locket

{T}: Add {W} or {U}.
{W/U}{W/U}{W/U}{W/U}, {T}, Sacrifice Azorius Locket: Draw two cards.