Air Commodore Ian Stewart left school in 1976 as a Cadet Warrant Officer having been awarded the Duke of Edinburgh Silver Award, a basic gliding certificate and a flying scholarship.  He went on to study Aeronautical and Astronautical Engineering at Southampton University as an Acting Pilot Officer with an RAF University Cadetship. 

Having completed Officer Training at RAF Cranwell in 1980 he remained to complete basic flying training before moving on to RAF Valley for advanced training.  He was selected to become an instructor and after completing Central Flying School training at RAF Leeming, he was posted to RAF Linton-on-Ouse in 1983 as a Qualified Flying Instructor where he flew over 1000 hours on the Jet Provost basic trainer. 

In 1986 he converted to the Phantom FGR2 and served on 92 Squadron, RAF Wildenrath in Germany, as the Squadron Qualified Flying Instructor.  He moved back to 228 Operational Conversion Unit at RAF Leuchars in 1989 before converting to fly the Tornado F3.  In 1992 he moved from Leuchars to RAF Coningsby and joined the Tornado F3 Operational Conversion Unit 56 (R) Squadron as a flight commander. In 1994 he joined the staff at 11 Group Headquarters at RAF Bentley Priory, serving on the Air Defence training desk. 

At the end of 1996 he completed the Joint Service Defence College course at Greenwich.  He then commanded the Flying Training Development Wing at RAF Halton where he was responsible for devising a training strategy for fast jet pilots.  In 1999 he served in the Defence Crisis Management Centre in MOD as a Kosovo briefing officer and completed a short tour within the former Directorate of Public Relations (RAF).  From April 2000 to October 2002 he was the Officer Commanding 56 (R) Squadron at RAF Coningsby.

After achieving over 1000 flying hours on the Tornado F3 he joined the UK Permanent Joint Headquarters at Northwood as the J5 Plans SO1 Deployable Liaison Officer and was a member of the Operation TELIC planning staff responsible for the UK's contribution to Coalition operations in Iraq. In 2003 he was posted to Ramstein Air Base, Germany, where he served as the A3 Division Head and United Kingdom Senior National Representative within the NATO Component Command - Air Headquarters. In early 2004 he served as Assistant Chief of Staff (Air) within the International Security Assistance Force in Kabul, Afghanistan, and was awarded the NATO Meritorious Service Medal in 2006 for services to NATO.