Although all of the major organs have long since been formed, your little guy or gal's lungs are continuing to develop and mature, which is why you really don't want to deliver your baby any sooner than absolutely necessary.
No longer the peanut he once was, your little man now weighs about 4 pounds and measures 17 inches in length, from crown to heel. He probably won't get too much taller, but he'll hopefully pack on a few more pounds before birth so that you have some sweet little fat rolls to pinch. By this point in pregnancy, many dads and other baby-lovers are actively talking to your stomach. Although it might seem silly on the surface, babies at this stage are more than capable of hearing outside voices, which they might even recognize soon after delivery. You don't have to bend over to address your belly directly, however, since he hears your particular vocal stylings every time you speak or sing along with Britney Spears in the car.
Since you're well into the third trimester, it's time for you to stop flying, although some airlines allow pregnant mothers to fly until the last 30 days of your pregnancy. Feel free to continue other activities you enjoyed throughout your pregnancy, like low-impact aerobics and swimming, unless your obstetrician has instructed you otherwise.