An aircraft 1 with a spiral inducing assembly 2 which is capable of inducing the aircraft to travel in a continuous spiralling motion without the aircraft rolling. Two fins 6 and 17 are attached to a tube 3 that is able to rotate around the encircled part of the fuselage. The fins 6, 17 are able to rotate in a pivoting manner on the rotatable tube 3 with respect to the rotatable tube 3, thereby changing their pitch relative to the longitudinal axis of the rotatable tube 3. Fin 6 is larger than fin 17. The difference in sizes between the fins makes the larger fin 6 exert a greater force on the rotatable tube 3 than the smaller fin 17 when the fins are pitched in unison. The aerodynamic imbalance between the fins thus causes the rotatable tube 3 to rotate. When pitched at an angle to the longitudinal axis in unison, both fins 6, 17 would exert a lateral force on the rotatable tube 3. Thus, as well as forcing the rotatable tube 3 to rotate, the fins 6, 17 would also push the rotatable tube sideways. But as the rotatable tube is pushed sideways, it rotates, and hence the lateral direction of push constantly revolves, causing a spiralling motion of the aircraft when in flight.