New Delhi, 7 Jan, 2008 : With fuel comprising 40% of the total cost, airlines, especially low cost carriers, are trying to find out means of optimizing fuel efficiency. Airlines globally are stressing on adopting various models to save fuel and are also following a strict regime of regular aircraft maintenance including complete aircraft wash, restoring of paint on the aircraft surface, smoothening of dents and projections on the aircraft on a fortnightly basis to minimize fuel consumption.