Stationary. The speed of the stator field with respect to stator surface will be Ns and the speed of rotor with respect to the stator surface will be N. The speed of the magentic field of the rotor with respect to the rotor will be s x Ns . Therefore the speed of the rotor field with respect to stator surface is equal to rotor speed of the motor and rotor field with respect to rotor.
N + s x Ns = Ns ( 1-s ) + s x Ns = Ns
Therefore the relative motion between stator field and rotor field will be stationary or zero.