This paper reports the results of thermal comfort and indoor air quality studies in forty-three flights with a duration of more than one hour. The measurements were performed continuously during the whole flight (from the departure gate to the arrival gate) and the parameters monitored were temperature, relative humidity and carbon dioxide concentration. The results were then compared with the ASHRAE Standards for the thermal and indoor air quality. The evaluation of the indoor air quality was based mainly upon comparison of the carbon dioxide concentration with standards in indoor environment: carbon dioxide, is an excellent indicator of indoor air quality. The relative humidity level was far lower than the limit set by the ASHRAE Standard (55-92). The level of carbon dioxide concentration in most of the flight was higher than what recommended by the ASHRAE Standard (62-89). The low level of humidity and high level of carbon dioxide concentration indicate that the crew and the passengers were dissatisfied with thermal comfort and the quality of the air in the cabin.