Aird was born in Aldershot, Hampshire. She was spotted by a casting Director aged nine whilst at Bush Davies Ballet School, and starred in the 1980 dramatisation of the H. G. Wells novel The History of Mr Polly. In 1981 she portrayed the young Elspeth Huxley in the television adaptation of the latter's autobiographical book The Flame Trees of Thika.
In 1981 she portrayed Elspeth Huxley in The Flame Trees of Thika. In 1982 she starred as the young Beatrix Potter in The Tale of Beatrix Potter. She was seen in The Happy Valley in 1987 with Denholm Elliott in which she played a schoolgirl in Kenya in the 1930s. As well as small parts in various television series, Aird became known for playing Nancy Thorpe/Garvey in Soldier Soldier. In 2000, she starred as Frankie Wharton in Waking the Dead. Aird has done voiceover for various BBC natural history projects (including Wild Mallorca), as well as various TV advertisements. In 2007, she played a clinical Psychologist, in Channel 4’s drama, 'Secret Life', and in 2009 took a leading role in Talkback Thames's Monday Monday.