A fly-in is a pre-arranged gathering of aircraft, pilots and passengers for recreational and social purposes.
Fly-ins may be formally or informally organised, members of the public may or may not be invited, the gathering may be at an airport or in a farmer's field.
Fly-ins can be aimed at specific aircraft classes, such as taildraggers, warbirds, experimental aircraft or specific aircraft models. They may be organized by a national organization, such as the Canadian Owners and Pilots Association or the Experimental Aircraft Association, the airport owner or authority, a flying club, an aircraft type club or by a group of friends meeting perhaps for a barbecue and to socialize.
The term "fly-in" is not formally defined in the aviation legislation of many countries and it may refer to a range of events, while in others it has a specific legal meaning. For example, in Canada fly-ins may not legally include air displays or competitive flying.
Both fly-ins and airshows evolved out of the first aviation meets held in the pioneering days of flying, early in the twentieth century, before the First World War.
Although there were some minor aviation meets in France earlier in 1909, at Port-Aviation south of Paris, in Douai and in Vichy, the first major international aviation meet was the Grande Semaine d'Aviation (English: Grand Week of Aviation) held in Reims, France between 22–29 August 1909. The event attracted some of the world's foremost pilots of the day, including Louis Blériot, Henry Farman, Léon Delagrange, Hubert Latham, Charles de Lambert, Louis Paulhan, Roger Sommer, Claude Grahame-White and one American, Glenn Curtiss. The event was primarily a competition for record setting. Curtis set a speed record of 80 km/h (43 kn) flying a biplane he had designed, winning the first race for Gordon Bennett Coupe Internationale d'Aviation. Henry Farman set a distance record of 180 km (97 nmi) in just over three hours. Hubert Latham won the altitude contest by attaining 155 m (509 ft). The event attracted large crowds of spectators including 3,000 from the United Kingdom and 2,000 from the United States. None of the aircraft were flown-in, but arrived via ground transport and assembled in place.