⁶ CO₂ and NO_x values per passenger-kilometre.
⁷ Averaged Perceived Sound Volume Reduction (EPNLdB) according to ICAO Annex 16 conditions for fixed-wing aircraft (Chapter 10 for CS-23 aircraft and Chapter 14 for CS-25 aircraft). 20% noise reduction is equivalent to 3 dB reduction. 30% of noise reduction is equivalent to 5 dB reduction.
⁸ Only fossil fuel concepts, excluding the innovative E-Short Take-Off and Landing (STOL) hybrid-electric commuter concept.
⁹ Surface area Reduction of L_den contours for 60-65 dB (A) noise levels at the European airports considered.