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 alveolar sacs consist of many alveoli and are composed of a single layer of epithelial tissue. There are about 700 million alveoli in the adult lung. The average, healthy adult lungs hold about 13 to 13.5 pints of air (about six liters). The alveoli are considered the functional unit of the lung. In the spaces between the alveoli of the lungs is elastic connective tissue which is important for exhalation. The alveoli are surrounded by a network of pulmonary capillaries.