No. 4 Flying Training School is a Royal Air Force military flying training school, which manages Advanced Fast Jet Training (AFJT) from its base at RAF Valley in Anglesey, Wales. Its role is to provide fast jet aircrew to the Operational Conversion Units for the RAF's jet attack aircraft, the Eurofighter Typhoon and the Lockheed Martin F-35 Lightning II. No. 4 FTS has primarily provided advanced flying and more recently jet aircraft training to aircrew students, although during World War II it was called upon to take part in offensive operations, a role it took on with great success.