Many doctors believe this decline in hormone levels triggers the symptoms of PMS. Changes in brain chemicals or deficiencies in certain vitamins and minerals may also play a role. Too many salty foods, alcohol, or caffeine may make symptoms worse as well.
There have been countless flights made since the invention of the airplane by the Wright Brothers in 1903. It should come as no surprise that the first commercial flight in history occurred in the United States. In fact, it occurred on January 1, 1914, three years before the United States entered the first World War.
Commercial aviation is a massive industry involving the flying of tens of thousands of passengers daily on airliners. Most airplanes are flown by a pilot on board the aircraft, but some are designed to be remotely or computer-controlled. The Wright brothers invented and flew the first airplane in 1903, recognized as the first sustained and controlled heavier-than-air powered flight.