A flap advisory system provides an advisory to a pilot informing that a speed of the aircraft should be attended to because of a current or desired flap setting. More specifically, the flap advisory system compares a measured airspeed of the aircraft either directly to a flap placard speed or to a marginal speed range set below the flap placard speed for a given flap setting. If the measured airspeed is determined to be excessive then the system provides an advisory indicating the airspeed is too fast. Further, the system may provide an advisory when a movement of a flap handle is detected such that continued movement of the flap handle would place the flaps in a setting that is inappropriate for the measured airspeed.