Is Kitesail Skirmisher legal in Standard, Modern, and Commander?

Kitesail Skirmisher is legal in: Legacy, Vintage, Commander, Pauper.

What type of card is Kitesail Skirmisher?

Kitesail Skirmisher is a Creature — Human Pirate. Its oracle text reads: "Flying Whenever this creature attacks, another target creature attacking the same player or planeswalker gains flying until end of turn. Encore {4}{U} ({4}{U}, Exile this card from your graveyard: For each opponent, create a token copy that attacks that opponent this turn if able. They gain haste. Sacrifice them at the beginning of the next end step. Activate only as a sorcery.) Power/Toughness: 3/1"

Kitesail Skirmisher

Creature — Human Pirate

Flying

Whenever this creature attacks, another target creature attacking the same player or planeswalker gains flying until end of turn.

Encore (, Exile this card from your graveyard: For each opponent, create a token copy that attacks that opponent this turn if able. They gain haste. Sacrifice them at the beginning of the next end step. Activate only as a sorcery.)