Skywriting is a form of advertising in which a pilot is contracted to spell out a brief slogan or catchphrase in letters formed by smoke. In general, a customer would designate a specific place and time for the skywriting to appear, usually over a large outdoor forum or beachfront. The message would only last as long as winds were relatively calm and the sky was clear. Single plane skywriting has largely been replaced by multi-plane 'skytyping', a computer-controlled method involving timed puffs of smoke from a synchronized row of aircraft.
The first official skywriting demonstration took place over New York City in November of 1922, but several sources list 1912 as a significant year as well. During an airshow in the Midwest that year, a pilot used standard issue Army smoke grenades to demonstrate the effectiveness of airplanes as battlefield signaling devices. Early military pilots and stunt performers also used smoke to better define their aerial maneuvers for spectators, occasionally spelling out letters for effect. By the 1920s, rudimentary skywriting was already be used commercially in some smaller markets.
In November of 1922, a skywriting pioneer and British Royal Air Force (RAF) pilot named John Savage sat with the president of the American Tobacco Company, George Hill, as a fellow RAF ace pilot named Captain Cyril Turner flew into position over New York City. Captain Turner spelled out "HELLO USA CALL VANDERBILT 7200" in white smoke. Over 47,000 people called the number, which happened to be the Vanderbilt Hotel where George Hill was staying. Hill became convinced that John Savage's skywriting advertisements would work well to promote his Lucky Strike® cigarettes.
Skywriting continued to grow in popularity as both an advertising medium and a personal message service. Customers could request anything from "Eat at Joe's" to "Will You Marry Me?" Messages and slogans would naturally have to remain short, but even a simple phone number could generate a lot of curious potential customers for a small investment.
The expansion of the national highway system after WWII spelled the beginning of the end for the skywriting industry. Instead of posting a few words in a fickle sky, advertisers could now fill entire billboards with all sorts of graphics. A captive audience of thousands would pass by these new placards every day, unlike the precious few who would encounter a typical skywriting message. Many aerial advertising companies turned to permanent banners pulled behind low-flying aircraft instead.
Some skywriting is still performed today, although only a select number of pilots retain the skills necessary for the job. The smoke is usually created by judiciously spraying paraffin oil directly on the hot engine manifold near the tail section of the plane. The pilot decides when smoke is needed to draw one section of a letter at a time. A spotter on the ground may also assist the pilot during trickier maneuvers.
The choreography involved in traditional skywriting can be challenging. Modern skytyping, on the other hand, requires a steady formation but no letter writing maneuvers. Puffs of smoke are released according to a master program in a computer. This method allows for simple graphics and more elaborate messages, even if it lacks the derring-do aspect of traditional skywriting.