In this paper a longitudinal control system has been designed for a 2 Kg payload Unmanned Aerial Vehicle using classical PID controller. To overcome the difficulty in tuning the PID gains to the required values, different nature inspired techniques have been used, for the Integral Squared Error (ISE) parameter optimization on UAV dynamic data at a specified trim condition. For this purpose, the penalty function that has been chosen includes time domain specifications as constraints. Finally all the results are compared for optimum PID parameters.