Many new future sustainable aircraft concepts have (electric) propeller propulsion. However, the noise and vibration generated by propeller propulsion might create discomfort for passengers. In the Clean Sky 2 project ‘ComfDemo’, all factors influencing comfort and discomfort are studied, with the aim to improve comfort experience for eco airplanes. The results show that noise, vibration and seat are the most mentioned factors influencing discomfort. The flights without passengers showed different noise characteristics, which makes test flights with passengers inevitable. Noise certainly needs attention, but anthropometrics as well as for instance elbow-elbow width is greater than the 18” seat width for many passengers.