FS98 EYA Air File For Rutan Pond Racer. The aircraft, projected by Burt Rutan as a more powerful and flexible twin-prop hunter remained a prototype. By this EYA (Enjoy Your Aircraft) .air file very direct and continuously well dominable controlling of flight should be provided. FS98 is intended to be used with a force feedback joystick, and so is this .air file. By Christoph Ruhtenberg.