Emirates airlines, has started a San Francisco service where they achieve the longest green flight ever. The airlines plans to reduces their impact on the environment by introducing new techniques. Such techniques are by using the airport's electric supply while they are grounded rather than using the plane's auxiliary power. Also using a single engine while taxiing. Although the thing about this service is that the route taken will be different where the plane will fly near the North Pole, reducing the total distance traveled by the aircraft.
By changing the route, it reduces the carbon emissions and saves fuel. To read more of this click here.