for mounting the panels 15 to the frame members 2 3 therein means used for engagement between frame members 2 3 and panels 15 can be any mountable and demountable connection member known in the current state of the art e g u201c pc 01 u201d panel clip set supplied commercially by fastmount ltd or other connection members having similar function panels can be made of materials such as wood i e plywood plastic etc and any panel 15 mounted to the frame member 2 3 can be replaced with a new one or with a panel covered with a different decorative coating by being easily demounted therefrom panels 15 are mounted to the frame members so as to face the inner volume of the cabin moreover respective panel 15 can be easily demounted for fitting functional components such as light fixture power outlet etc in the rear part of the panel 15 that cannot be seen i e the space between frame members 2 3 in addition if desired a noise and or heat insulating material can also be fitted in the rear portion of the panels 15 the space between frame members 2 3 male 8 and or female connections 7 are formed at the ends of each frame member for being able to connect frame members 2 3 of the lateral.