Nanotechnology aside, air travel has always been an undeniably remarkable enterprise. Not only the ability to be airborne for stretches of time, but to endow colossally heavy machines with such capabilities is truly monumental.
To simplify the scientifics, jet engines function by sucking air through a compressor, then a combustor before introducing it to fuel. This mix generates an ignition which, in turn, causes thrust. Since the 1940s, they have evolved in capacity, efficiency and durability but the basic mechanics have remained the same. Spacecrafts are not too dissimilar in function, except their use of internal gases in order to significantly magnify the propagation velocity.
The sheer magnitude of these endeavours is reflected in the colossal fuel expenditure that is necessary to allow such huge machines to be airborne. As we become more environmentally savvy we naturally look at the areas with maximum environmentally damaging waste.
Of course, air travel is a large portion of this but what a waste it would be to scrap air travel when it was such a huge step for mankind (irony intended). So, many scientists are looking into ways to develop new fuels which can have a less damaging effect on the environment.
This requires looking at the chemical foundations of the fuel itself, even down to the smallest cells. The current cell makeup allows ions to be passed through the cell membrane via elements such as methanol or hydrogen, with platinum being used as the catalyst.
The problem with platinum, however, is that it is neglects to allow the passing of other ions like oxygen and it is a costly material. Of course this significantly diminishes the cell efficiency which means they burn out faster and are heavier.
So, the main focus for more eco-friendly fuel on a cellular level has been based around the removal, or at least reduction, of platinum as the catalyst and replacement with something more economical; both environmentally and in cost value.
Enter: nanotechnology. Nanotech fuel cells are already being employed in other industries such as consumer technology; laptops/smartphones, etc., using longer lasting direct methanol fuel cells (DMFCs) in a cartridge based battery rather than traditional batteries. Despite being longer lasting, they still utlize platinum so their cost is still fairly high. This is being addressed in tests which vary platinum density and introduce control substances such as cobalt-coated graphene or silica nanoparticle-facilitated proton exchange membranes.
Another way in which nanotech is being utilised for airborne endeavours is heat management in rocket engines. New developments in rocket engines have made it necessary to create a heat exchange unit to enable rockets to withstand enormous temperatures, with nanotech at the forefront of such heat exchange solutions, there is no telling where the evolution of air travel will take us.