1. Introduction

Since 1960, the worldwide air passenger traffic has been growing at an average yearly rate of 9% and it has been estimated that it will continue to grow with a 5–7% rate into the foreseeable future. One obvious reason for such growth is technological advances in aircraft system leading to improved aircraft-efficiency and reduced cost. However, with increased air traffic, the aircraft industries are also facing challenges in terms of \(\mathrm{CO}_{2}\) emission and safety [1]. Today, air transport is responsible for 2% of the total man made \(\mathrm{CO}_{2}\) emission which is estimated to increase further to 3% by 2050. In this regard, the Advisory Council for Aeronautics Research in Europe has set several goals to be achieved by 2020 including 50% reduction of \(\mathrm{CO}_{2}\) emissions; an 80% reduction of \(\mathrm{NO}_{X}\) emissions, and a 50% reduction of external noise [2, 3]. Thus, currently, the aircraft industries are driven by three major objectives - 1. improving emissions 2. improving fuel economy and, 3. reducing cost.