On-time departure performance is important for airlines that seek the highest satisfaction of their passengers. The main component of achieving on-time departure is being able to complete the turnaround operations of an aircraft within the scheduled time. To address this problem, the present paper examined planning and scheduling of turnaround operations in the low cost airline industry. A mathematical model, named 'TurnOper_LP' was developed for a low-cost Turkish airline to identify the critical path of turnaround operations and the optimal turnaround time. The results of the model in terms of optimised turnaround times are then analysed and an example of schedule of turnaround operations is presented.