Haptic support systems are commonly designed as feedback systems that track a known trajectory. However, when a pilot performs a maneuver in a free airspace, the desired trajectory is not known a priori. Thus, an estimation of the pilot intended trajectory is needed. This paper investigates the estimation of the pilot desired trajectory for designing a haptic support system that helps pilots perform helicopter maneuvers in a free airspace. A probabilistic algorithm is implemented to estimate the pilot intended trajectory according to the actions made on the control devices. The haptic aid is developed as a feedback controller able to follow the estimated intended trajectory. Two simulations were conducted to test the effectiveness of the proposed algorithm. First, filtered step-wise pilot control inputs were considered. Then, real pilot inputs were employed, which were recorded in a lateral reposition maneuver performed on a motion simulator. The developed algorithm was able to recognize the intended path according to the given pilot inputs in both scenarios.