Air is a Japanese visual novel developed by Key which was originally released as an adult game on September 8, 2000 playable on personal computers (PC) as a CD-ROM. Subsequent versions with the adult content removed were sold playable on the PC, Dreamcast, and PlayStation 2 (PS2). The PC version with adult content was re-released with added support for Windows 2000/XP under the name Air Standard Edition on April 8, 2005. The last releases of Air were made available to play on the PlayStation Portable (PSP), and SoftBank 3G and FOMA cell phones.

The gameplay in Air follows a plot line which offers pre-determined scenarios with courses of interaction, and focuses on the differing scenarios of the three female main characters. The game is divided into three segments—Dream, Summer, and Air—which serve as different phases in the overall story. One of the goals of the original version's gameplay is for the player to enable viewing of hentai scenes depicting the protagonist and one of the three heroines having sexual intercourse. The title of the game is meant to reflect the prominent themes of the air, skies, and use of wings throughout gameplay.

Air has made transitions into other media. A manga series based on the visual novel was first serialized in the Japanese magazine Comptiq and published by Kadokawa Shoten; the manga ran between August 2004 and February 2006 and was illustrated by Japanese artist Yukimaru Katsura. A thirteen-episode anime series created by Kyoto Animation aired in Japan between January and March 2005. A subsequent release of two episodes entitled Air in Summer aired in August and September 2005. While the anime was still airing, an Air film by the animation studio Toei Animation hit theaters in Japan in February 2005. The anime series, plus the two-episode Air in Summer and the film were initially licensed and released in North America by ADV Films, but the license for these titles was transferred to Funimation in July 2008. A set of nine drama CDs were also released, published by Lantis between August 2005 and January 2006.