While it has nothing to do with the invention in the article (which is just about restructuring cabin airflow): air in an airplane is constantly introduced from

While it has nothing to do with the invention in the article (which is just about restructuring cabin airflow): air in an airplane is constantly introduced from outside, pressurized taps from the compressor inside the engine(s). Pressure is maintained at a set level by a valve that controls how much air escapes the plane. Most airliners will also have a recirculation/filtering/conditioning system. http://en.wikipedia.org/wiki/Environmental_control_system_%28aircraft%29 http://en.wikipedia.org/wiki/Environmental_control_system_%2... If that's what you're asking. Not entirely sure.