Extended reality (xR) Head-mounted displays (HMDs) have grown in popularity and capability over the last decade. Their use across many industries has increased proportionally. Use of xR HMDs has been of particular interest in defence training because of their low cost and rapid technological improvement. However, not enough research has been performed on the training effectiveness of xR HMD technology for military training. The current study investigated the training effectiveness of a virtual reality (VR) HMD-based simulator in pilot training within the Royal Canadian Air Force (RCAF). We performed a reverse transfer of training experiment comparing Novice and Expert Pilots on the Overhead Break Flight Manoeuvre in a VR HMD-based simulator. Participants repeated the Overhead Break 7 times during a 45-min experiment. Instructors evaluated participant performance of each Overhead Break attempt, assigning a score from 1-5 on a validated criterion used by the RCAF for pilot evaluation. We hypothesized that Expert pilots would perform significantly better than Novice pilots on initial Overhead Break trials. This would demonstrate that Expert pilots find the VR HMD-based trainer similar to live flying of the same aircraft represented in VR, in part validating the VR HMD-based trainer. Findings indicated that Expert Pilots performed significantly better than Novice Pilots on the Overhead Break throughout the experiment as predicted. Importantly, Novice Pilots improved significantly on the Overhead Break over the course of the experiment. Cybersickness scores from using VR over the length of the 45-min experiment was negligible. Taken together, these findings indicate that the VR-HMD based trainer is a valid method for training the Overhead Break. Future research should validate VR-HMD based simulators as done in the present study for other flight manoeuvres and investigate if their use significantly improves student pilot performance. This will broaden our understanding for the successful integration of VR-HMD based simulators in military flight training.