Sport of racing aircraft. Air Racing is nearly as old as powered flight, and got its start in the early part of the 20th century. The heyday of the sport was in the late 1920s, when the premiere races were held in Cleveland, Ohio. In the early days of Air Racing, most of the airplanes were custom-built creations of individual designers, intended solely for racing. However, following World War II, these custom racers began to be replaced by the modified warbirds that continue to dominate the sport to this day. Air racing fell out of public favor after the disastrous crash of the modified P-51 Mustang known as the "Beguine," which resulted in the deaths of a woman and her child in Cleveland. The sport has made a bit of a comeback, though, with the most well-known races being held in Reno, Nevada.
There are two main types of air races. Transcontinental races, as the name suggests, are long races that span entire continents. Flying across the United States is a popular goal for a transcontinental race. More popular, though, are the shorter-duration pylon races. These races are held on relatively short courses which are marked by tall pylons which the airplanes must fly around. Transcontinental races are quite rare at present, and nearly all air races are of the pylon variety.
Even within the pylon race type, there are subclasses. There is a class, for instance, that consists solely of Biplanes. Since these airplanes are relatively slow and maneuverable, Biplane tracks tend to be short and tight. These same tracks are often used for Formula-1 airplanes, which are small, lightweight fiberglass airplanes. Another class consists of AT-6 Texans, which were originally intended as advanced training aircraft for military pilots. These airplanes are rather slow and not very maneuverable. The most popular class, though, is the Unlimited class. As the name suggests, this class is the least restrictive, and highly-modified airplanes are the norm. Most are modified WWII-era fighter aircraft. These include the P-51 Mustang, the P-38 Lightning, the F8F Bearcat, the F4U Corsair, and the Hawker Seafury. These airplanes typically have more powerful engines installed, and have significant airframe modifications as well. Unlimited-class aircraft can reach speeds of over 500 miles per hour!