This paper analyzes the impact and benefits of directional antennas in improving the throughput scaling law of a large wireless network in an information-theoretic perspective. More specifically, we deal with a general scenario where the beamwidth of each node can scale at an arbitrary rate relative to the number of nodes in the network. We then introduce an elastic routing protocol, which enables to increase per-hop distance elastically according to the scalable beamwidth, while maintaining a constant average signal-to-interference-and-noise ratio at the receivers. Our main results indicate that this elastic routing can exhibit a much better throughput, compared to the conventional nearest-neighbor multihop, and eventually leads to a linear throughput scaling. The gain comes from the fat that more source-destination pairs can be activated simultaneously with the boosted antenna gain. In addition, our work is extended to a hybrid network scenario using infrastructure.