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).
The alveoli are only one cell thick, allowing the relatively easy passage of oxygen and carbon dioxide between the alveoli and the capillary. One cubic millimeter contains 170 alveoli and the area of alveoli is on average 70 square meters. The number of alveoli differs between people and larger lungs have more alveoli.