The fact that the plane is made of composites instead of aluminum makes the passengers more comfortable. Most passenger planes fly so high that they needs to pump air into the cabin so the passengers can breathe. Most planes pump in enough air so that the passengers feel like they are at about 8000 feet (2400 meters). But since the 787 uses composites, which is stronger than aluminum, the plane can pump in more air so the passengers feel like they are at about 6000 feet (1800 meters). The composite is also less vulnerable to corrosion, so the plane can have a higher humidity than most other planes. Boeing says that these improvements will make passengers feel better after a long flight.