Valkyrie Aerial Unit

Flying is an evasion ability.

A creature with flying can’t be blocked except by creatures with flying and/or reach. A creature with flying can block a creature with or without flying. (See rule 509, “Declare Blockers Step,” and rule 702.17, “Reach.”)

Multiple instances of flying on the same creature are redundant.

To “surveil N” means to look at the top N cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.

If an effect allows you to look at additional cards while you surveil, those cards are included among the cards you may put into your graveyard and on top of your library in any order.

If a player is instructed to surveil 0, no surveil event occurs. Abilities that trigger whenever a player surveils won’t trigger.

An ability that triggers whenever a player surveils triggers after the process described in rule 701.42a is complete, even if some or all of those actions were impossible.

Affinity is a static ability that functions while the spell with affinity is on the stack. “Affinity for [text]” means “This spell costs you {1} less to cast for each [text] you control.”

If a spell has multiple instances of affinity, each of them applies.