Air is a Japanese visual novel developed by Key, and released on September 8, 2000. The original version, first available on the PC, contains a minimal amount of adult-only content of a sexual nature. Subsequent "clean" versions were sold playable on the Dreamcast, PlayStation 2. The PC version with adult content was re-released with added support for Windows 2000/XP under the name Air Standard Edition. The last releases of Air will be available to play on the PlayStation Portable and the SoftBank 3G cell phone.

The gameplay in Air follows a linear plot line where the player interacts at predetermined times to choose predetermined options that appear on the monitor. The game was developed so that the focus for the player would be an intricate plot and the appeal of the three female main characters. The title of the game is meant to reflect the prominent themes of the air, skies, and use of wings.

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 10, 2004 and February 10, 2006 and was illustrated by Japanese artist Yukimaru Katsura. A thirteen-episode anime series created by Kyoto Animation aired in Japan between January 6, 2005 and March 31, 2005. A subsequent release of two episodes entitled Air in Summer aired on August 28, 2005 and September 4, 2005. While the anime was still airing, an Air movie by the animation studio Toei Animation hit theaters in Japan on February 5, 2005.

There are important locations featured in Air that are based on those of the Kami city in Hyogo Prefecture, Japan. Air is set in the Kasumi district of Kami; during the course of the series' creation, Kasumi was an individual town that has since merged with two others to form the city of Kami. Many of the locales in Air, such as the seawall, the train station, the shrine, and the school are real places. The summer season offered bright, sunny skies for the town during the day. In the manga adaptation, the town is described as a "quiet town with few people...with nothing but beaches and countryside."

As indicated by the title, air, skies and wings are important themes: Yukito is searching for the "girl in the sky" and Misuzu believes that her other self is flying in the sky above her. Other characters show a similar relationship to the sky, such as Minagi who is a member of the Astronomy Club and Michiru who has a fondness for bubbles that float in the air. Kano wants wings to fly, and Kanna already has them. Misuzu names a crow she finds Sora (空), meaning sky. Another major theme is the maternal bond, as the four heroines' stories, as well as Yukito's, revolve around their mothers, either biological or adoptive.

One of the sub-themes in the story is magic. Uraha, Yukito's mother, and Yukito himself have the ability to use magic, though Yukito is the least skilled among them. Kano was told by her sister that when she grows up and takes off her yellow ribbon, she will gain the power to do magic.

Set in the middle of summer, Air's story revolves around three girls whose lives are connected to the same man. Yukito Kunisaki, the main protagonist, is a showman traveling across Japan, continuing his mother's search for the "girl in the sky".

At the beginning of the story, Yukito comes across a small seaside town where the story takes place. On his first day in town, Yukito tries to earn money by putting on a mysterious puppet show for kids he finds by manipulating a doll magically without strings. Yukito is unsuccessful in gaining the children's favor, and the children end up running off without paying him for his performance.

Defeated after not getting any money, and not having enough for even a meal, Yukito falls asleep on a seawall near the beach. He awakens the next day to find beside him a young girl who introduces herself as Misuzu Kamio – a sincere yet clumsy girl who is eager to become friends with him. Misuzu persistently attempts to play with him, while Yukito tries to refuse her efforts. When Misuzu finds out Yukito has not eaten anything since the day before, she suggests that he come to her house and eat for the time being. Lured by a chance to eat, Yukito follows her back home. Upon learning of Yukito's lack of lodging, Misuzu suggests that he stay at her home until he can find a place in town while he earns money, despite Yukito's hesitance to go along with her plan. That night, Haruko – Misuzu's aunt and foster-mother – comes home and after Yukito and Misuzu persuade her, it is decided that he will stay with them on two conditions: that he sleeps in the shed, and that he shares a drink with Haruko.

As Yukito resides with Misuzu, he meets two other girls, Kano Kirishima and Minagi Tohno, who like Misuzu, have strange personalities connected with mysterious pasts. Before long, a legend of "one thousand summers" begins to unfold where the mysteries of the past are framed by the odd relationship between Yukito and Misuzu.

On November 17, 2004, a teaser DVD named Air ~prelude~ was produced containing interviews with the cast, clean opening and ending sequences, and promotional footage of the anime itself. It was a limited edition DVD, with only 20,000 copies produced.

An anime based on the original visual novel aired in 2005 on TBS's BS-i satellite broadcasting network. The first episode, ~breeze~ (かぜ kaze), was aired on January 6, 2005. The anime series comprises thirteen episodes, which consist of twelve main episodes and one recap episode. The anime also follows the game by splitting the series into three parts; Dream (eps 1-7), Summer (eps 8-9), and Air (eps 10-12), with the recap episode (ep 13) following. The theme songs from the Air visual novel are used for the anime's opening theme, ending theme and soundtrack.

At the end of episode thirteen of the Air anime, there was a teaser for a special addendum to the series, entitled Air in Summer. The two episodes aired on August 28, 2005 and September 4, 2005 respectively on BS-i. The DVD was later released on October 5, 2005 in Japan.

On December 22, 2006, Air became one of the first anime series to be released in Blu-ray Disc format. The release came in a four disc box set containing the twelve main episodes and the two Air in Summer episodes. The box set retails for 29,800 yen (~US$247.66), though this is still cheaper than buying the seven individual DVDs, including Air in Summer.

On April 27, 2007, ADV Films co-founder and executive Matt Greenfield announced the acquisition of both the anime series and the movie during a panel at Anime Matsuri, South Texas' anime convention. Volume one of the four-disc Air series hit store shelves on August 14, 2007, and the Air movie will be released on December 11, 2007.

- From Wikipedia