FlyingFlying 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. (CR 702.9)
Spirits you control get +1/+1 for each time you've
castTo cast a spell is to take it from the zone it’s in (usually the hand), put it on the stack, and pay its costs, so that it will eventually resolve and have its effect. A player may cast a spell if they have priority. See rule 601, “Casting Spells.”
To cast a card is to cast it as a spell. (CR 701.5) your
commanderA designated card for a Commander deck, governed by the command-zone, color-identity, and Commander rules. (CR 903) from the command zone this game.
Whenever a Spirit you control enters, you may pay
. If you do, return this card from your graveyard to the battlefield.