An item may sometimes be described as being a virtual item when it is a representation or non-tangible abstraction of the physical object, or is a functional emulation or simulation of it.
Enhancing the efficiency of propulsion can reduce fuel consumption and emissions in the air transport sector. Novel concepts such as multiple distributed propulsion systems and integration of propulsion into the airframe could help achieve goals.
EN 
CS
DE
ES
FR
HU
IT
PL
PT
РУ
SK
TR
УК
AR
中文
