In this letter, we analyze a terrestrial wireless communication network assisted by an aerial intelligent reflecting surface (AIRS). We consider a packet scheduling problem at the ground base station (BS) aimed at improving the information freshness by selecting packets based on their ages of information (AoIs). To further improve the communication quality, the trajectory of the unmanned aerial vehicle (UAV) which carries the IRS is optimized with joint active and passive beamforming design. To solve the formulated non-convex problem, we propose an iterative optimization problem based on successive convex approximation (SCA) algorithm. The simulation results show significant performance improvement in terms of weighted sum AoI, and the SCA solution converges quickly with low computational complexity.