The famous Air is the second movement from Bach’s Orchestral Suite No. 3 in D Major (BWV 1068). The movement really became famous more than 100 years after Bach’s death when the German violinist, August Wilhelmj, arranged it for solo violin and small orchestra. Wilhelmj took the liberty to transpose it down a full step, to C major, from Bach’s original key of D, thus allowing the violinist to play the entire melody on the instrument’s lowest string, the G string.
There are probably thousands of renditions of Air on the G String. One of my favorites is by the Jacques Loussier Trio. Enjoy it here.