Leonardo Da Vinci grasped the basic principles of flight in the 15th century. Today, new flying machines are continually being developed, and we can sail through the air to our hearts 'content just by taking a comfortable seat in an aircraft cab in.
從十五世紀義大利藝術家達文西首先領悟機械飛行原理，到二十世紀各種動力飛行器的推陳出新，人類現在只消坐在機艙舒適的沙發中，就能在空中宛如平地般地來去自如。