SAS’ strategy is to replace older aircraft with newer ones. An example of the improvement is the A320, which has eighteen seats more than the MD-80 while reducing the fuel consumption and associated emissions by approximately 20% on a comparable flight. The 85 dB area in km² per departure is also reduced by approximately 55%.
It is also important to use the right size of aircraft on every possible occasion. That is why SAS uses Boeing 737NGs and A320 family aircraft of different sizes. They have 120, 141 and 183 and 141, 168 and 198 seats, respectively. This entails great flexibility according to demand, which guarantees the lowest possible total emissions at any given time.
Flying aircraft that are too big generates unnecessary emissions even if it generates a better theoretical result per available seat kilometer. If we look at a Boeing 737NG on a typical domestic route in Norway, it is evident that the fuel consumption and corresponding emissions are lower in a smaller aircraft. When using a B737-800 with 183 seats and 141 passengers onboard, the total fuel consumption (in average) is approximately 6–7% higher than a full B737-700.