Millimeter wave tilted beam horn antennas (mmWave) hold immense potential for reducing atmospheric absorption and multi-path effects that hinder signal quality at these frequencies. However, conventional design techniques employ bulky structures, have complex geometries, don't utilize low-cost air-filled SIW technology (AFSIW), suffer from poor bandwidth, and exhibit comparatively poor gain and low elevation scanning coverage. To address these concerns, an AFSIW horn antenna with a tilted beam is proposed for the first time. The design exhibits a large bandwidth over the entire V-Band, a superior gain of 15.51 dBi, and a large elevation scanning coverage. Furthermore, the work also proposes an AFSIW multibeam antenna array utilizing these tilted-beam AFSIW horn antennas for the first time. This array finds application in urban-air-mobility (UAM), and satellite communication systems, where mitigating multi-path effects is crucial for enhancing signal quality. State of art performance is observed when the work is compared to reported advances in the literature. In conclusion, the work addresses a critical gap in tilted-beam antenna design but also paves the way for cost-effective, highperformance solutions for mmWave communication.