[2] He was a session guitarist before joining up in 1973 with former Bay City Rollers musicians David Paton and Billy Lyall in the band Pilot, contributing the harmony guitar parts to their hit single "Magic".

In 2019, Bairnson added guitar solos to two songs from Alan Parsons' new album, The Secret, specifically the tracks "Years of Glory" and "I Can't Get There from Here".

During his session career he played on more than a hundred albums in different styles, for artists such as Yvonne Keeley, Joe Cocker, Jon Anderson, Chris DeBurgh, Mick Fleetwood, and Neil Diamond.

After moving back to the UK in 2013, Bairnson got together with David Paton and produced an album called A Pilot Project where they paid homage to Eric Woolfson’s legacy.

His wife, Leila, announced on her Facebook page in 2018 that Bairnson had been diagnosed with a progressive neurological condition that affected his communication skills, so he would no longer play in public.