Celestial Enforcer

{1}{W}, {T}: Tap target creature. Activate only if you control a creature with flying.

Gale Swooper

Flying
When Gale Swooper enters, target creature gains flying until end of turn.

Defender (This creature can't attack.)
Attacking creatures you control get +1/+0.

Whenever Falconer Adept attacks, create a 1/1 white Bird creature token with flying that's tapped and attacking.

Flying
When Aven Gagglemaster enters, you gain 2 life for each creature you control with flying.

Target creature gets +2/+2 until end of turn. You gain 1 life for each attacking creature you control.

Thriving Heath enters tapped. As it enters, choose a color other than white.
{T}: Add {W} or one mana of the chosen color.

Enchant creature
Enchanted creature has defender and loses flying.

Flash
Flying
When Angel of the Dire Hour enters, if you cast it from your hand, exile all attacking creatures.

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