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.
Founded in Boise, Idaho in 1926, the carrier flew the first contract air mail flight in the U.S. on April 6, 1926, marking the first scheduled airline service in the country's history with flights between Pasco, WA and Elko, NV via Boise. In 1933, United began operating the Boeing 247, the first all-metal airliner.