Vault Skyward

Oracle Text

Target creature gains flying until end of turn. Untap it.

Card Rulings

1/1/2011 Vault Skyward can target any creature, including one that already has flying or is already untapped.
1/1/2011 For flying to work as an evasion ability, Vault Skyward must be cast before the declare blockers step begins. Once a creature has become blocked, giving it flying won’t change that.