Invasion of Kaladesh

(As a Siege enters, choose an opponent to protect it. You and others can attack it. When it's defeated, exile it, then cast it transformed.)

When this Siege enters, create a 1/1 colorless Thopter artifact creature token with flying.

Flying

Aetherwing's power is equal to the number of artifacts you control.

Crew 1 (Tap any number of creatures you control with total power 1 or more: This Vehicle becomes an artifact creature until end of turn.)