His first tour of duty was with No 2 Transport Squadron where he gained proficiency on the DC 3s, the Riley Herons, and the Avros. It was there that he was picked to become a Flying Instructor. He underwent Flying Instructor Training with the Pakistan Air Force and became a Qualified Flying Instructor. As a transport pilot, he has flown Antonov An 32b, HS-748 Avros, Y-8s, Y-12s, DC -3s and Riley Herons. And as a flying instructor, Air Chief Marshal Gunatilleke has taught many a pilot in the Chipmunk, Cessna 150, Dove, the Cessna 337, Riley Heron Avro, SF 260 TP Pucara, Y-12 as well as the Beechcraft B-200T. 

 Flying the SF 260 TP and the IA 58 Pucara, Air Chief Marshal Gunatilleke saw extensive action and participated actively in the support of all ground operations against the LTTE. His conspicuous gallantry earned him the Rana Wickrama Padakkama and the Rana Sura Padakkama. He has accumulated over 4000 hours of flying in his roles as a transport pilot, an attack pilot and as an instructor. He possesses a VVIP, Master Green Instrument Rating. He has also held the appointment of the Command Instrument Rating Examiner. 

 Air Chief Marshal Gunatilleke’s professional development included training at many overseas training institutions. Notable among them are the Command and Staff College, Pakistan, Joint Air Warfare College in India, Air Command and Staff College in Alabama, USA and National Defence College in Pakistan. He participated in the Executive Course of the Asia Pacific Centre for Security Studies in Hawaii. Air Chief Marshal Gunatilleke had the distinction of being a member of the first batch to be conferred with the Master of Science (Defence Studies) Degree in Management from the General Sir John Kotalawala Defence University. 

 During his career spanning over three decades, Air Chief Marshal Gunatilleke has commanded No 1 Flying Training Wing and No 2 Transport Squadron. He served as the Staff Officer Operations at Air Force Headquarters. He completed a tenure as Base Commander SLAF China Bay. As Base Commander SLAF Katunayake, Air Chief Marshal Gunatilleke was at the helm of the largest of the SLAF’s bases. 

 He was appointed to Air Force Headquarters as the Director Training in January 2008 and served in that capacity till he was called to take on the responsibility of the appointment of the Director Air Operations. In this capacity he was responsible for the direction of all air operations during the critical latter stages of the Humanitarian Operation, during which the SLAF broke all records in numbers of sorties flown, in the attack, surveillance, CASEVAC and transport roles. 

 His service decorations and medals include the Vadamarachchi Medal(1989), Armed Service Long Service Medal(1994), Riviresa Campaign Service Medal(1999), North & East Operation Medal(2000), SLAF 50th Anniversary(2001), Utthama Seva Padakkama(2003), Armed Service Long Service Clasp (2003), North & East Humanitarian Medal(2011), and the Vishishta Seva Vibushanaya(2011). 

 An Avid Sportsman, Air Chief Marshal Gunatilleke had the distinction of being a member of the Badminton National Pool. He has continued his involvement in sports in the sphere of sports administration as well having held appointments such as President National Rifle Association of Sri Lanka from 2007 to 2009, the Chairman Selection Committee -Badminton in 2010. He holds the appointment of Chairman,National Selection Committee since 2011. 

 Air Chief Marshal Kolitha Gunatilleke relinquished command of the Air force on 15th June 2015 and was appointed Chief of Defence Staff by HE the President. 

 Air Chief Marshal Kolitha Gunatilleke and his wife Roshani are the proud parents of Anushka. In his times of leisure and relaxation, he enjoys music, social dancing and reading.