This paper presents the work on integrating a Vision-aided Inertial Navigation System (VaINS) with orthophoto matching to cope with the GNSS failure. Normalized cross-correlation is used to match onboard camera images with geo-referenced aerial imagery. Image sequences captured at a 90˚ nadir angle by VaINS on a fixed-wing UAV is used. The integrated navigation results are compared against both a smoothed GPS-aided reference solution and the standalone VaINS solution during simulated GPS-denied intervals. The results demonstrate that the integrated approach significantly outperforms the VaINS-only method. This is a preliminary investigation within an ongoing work in orthophoto matching.