SkyMark, JetStar and others offer flights from Tokyo and other major cities in Japan to Naha. Low cost airlines such as Air Asia Japan and Peach Aviation now fly between Okinawa (Naha) and Tokyo Narita, Osaka Kansai respectively. Most Japanese airlines do offer deep discounts, but they MUST be bought in advance.
The alveoli are open to the environment so alveolar pressure (i.e. the pressure inside the lungs) is really the same as atmospheric pressure. Intrapleural pressure is the pressure of the air in the pleural cavity in which the lung sits (the space between the lung tissue and the chest wall).
In the alveoli, oxygen from the air is absorbed into the blood. Carbon dioxide, a waste product of metabolism, travels from the blood to the alveoli, where it can be exhaled. Between the alveoli is a thin layer of cells called the interstitium, which contains blood vessels and cells that help support the alveoli.