Commercial aviation is a significant source of humanity's carbon footprint and also one of the fastest growing. It currently accounts for about 2% of the total anthropogenic carbon dioxide production, and this number is bound to increase with the increased adoption of air travel.  Hence, developing airplanes that run on energy sources other than fossil fuels would prove significant in the fight against global warming.
One alternative source that has been extensively explored in the last half century is electricity. Electricity can be produced by sustainable means and then stored onboard to provide power.
The biggest advantage of electricity over fossil fuels is the fact that the former can be generated through sustainable means such as solar, wind, or hydroelectric power. In addition, electric powertrains have several advantages that lead to better overall efficiency. These include the ability to fly at higher altitudes, as the batteries don't require air, and distribution of power among several motors - which can achieve up to a five-fold increase in efficiency. [2,3]
However, the critical disadvantage of electricity is the weight of the energy source. Despite huge advances in the last quarter of a century, the energy density of current batteries is still around 2% of conventional fuels (7% when the increased efficiency of electric powertrains is accounted for). 
Electric aviation, while a promising idea, will not be feasible until major advances in battery technology are made to dramatically increase its energy efficiency. 
In the end, the move from fossil fuels needs to happen sooner rather than later if we hope to stall and reverse the damage already done to the environment by them.
© Moe Ayub. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
 C. von Kaenel, "Aviation Is First Global Industry to Limit Carbon Emissions," Scientific American, 7 Oct 16.
 G. C. Larson, "Electrical Power Will Change the Look of Aviation, " Air and Space Magazine, December 2015.
 N. Stockton, "NASA's New X-57 Electric Plane Looks Goofy but Packs Some Sweet Tech," Wired, 21 Dec 16.
 E. Adams, "The Age of Electric Aviation is Just 30 Years Away," Wired, 31 May 17.