Since 1974 Aviointeriors supplies airline companies with customized interior products. Focused its manufacturing, mainly, on passenger seat but has within its capability list, also, manufacturing of furniture, sidewalls, galleys, lavatories. The seat design is developed to be installed onto cabins for Boeing, Airbus, ATR and other passenger aircraft in accordance with TSO/ETSO design approval letter, referred respectfully to CS rules and FAR rules. Certification process for passenger seat, referred to Part 25, is developed on the integrity of the structure and occupant safety, conjunction to be made perfect with the functional, aesthetic and comfort performance. Due to the complexity of seat design on the customer request in terms of comfort to be offer to occupant inside cabin , kinematic simulation and ergonomic studies are performed with a frequency so high like the same made for the developing of a cockpit for a car, because of air travels, especially long distance, causing on physiological and psychological discomfort to passenger. Remember that sleeping is one of the common activities during the long haul flight but passenger is affected by a discomfort sensation also during the upright sitting posture. In the current paper, subjective and objective measurement method was described to evaluate the impact of seat design on passenger posture referred to an economy class aircraft seat passenger. Activity analysis in combination with the pressure mapping evaluation is currently used to establish a comfort measuring of aircraft passenger seats.