Providing Voice over IP in WLAN based wireless meshed networks is an important service for the future wireless internet. However, the transmission of small (voice) packets imposes high overhead which leads to low capacity for VoIP over 802.11 based multihop meshed networks. By combining several small packets into larger aggregated ones, it is expected that overhead can be significantly reduced thus incapacity for VoIP services. When mesh relay nodes aggregate small packets, there is an inherent trade-off regarding packet size. Aggregating more packets leads to larger packets, reduces the overall number of packets in the mesh and thus reduces multi-hop contention and packet loss due to collisions. However, such larger aggregated packets can lead to higher packet loss for a link that operates at low signal quality. For such links, aggregating fewer packets can be beneficial. Classical aggregation strategies typically operate end-to-end without considering those aspects and are therefore suboptimal. In this paper, we propose a new adaptive hop-by-hop aggregation scheme that calculates target aggregation sizes per each hop based on wireless link characteristics. Simulation results show that our approach is very effective, outperforms static aggregation schemes in various performance parameters and increases capacity for VoIP in meshed networks significantly