The airplane is currently the fastest mode of transportation, helping to connect nations and cities worldwide and enabling people to travel and reach any location on Earth. Government officials and environmentalists have been constantly monitoring the industry due to the yearly increase in the number of planes and passengers. The biggest contributor to global warming is the excessive quantity of carbon dioxide released into the atmosphere during air travel, and as the number of flights and passengers rises, so will the impact of aviation pollution. Environmental researchers estimated that 2.1% of the carbon dioxide pollution in the atmosphere was caused by airplanes in 1990.