In LTE, the antennas have a fairly significant downward angle since every cell uses the same set of channels as every other cell. Before LTE, there would be a frequency reuse pattern, so another cell a few miles away would be using the same spectrum. So even then they are aimed somewhat down rather than at the horizon, as you said. But with LTE it's much more significant.
MickeyElephant t1_ixt8g6h wrote
Reply to comment by FriendlyDespot in Bye-bye airplane mode: EU allows smartphones during flights by Zhukov-74
In LTE, the antennas have a fairly significant downward angle since every cell uses the same set of channels as every other cell. Before LTE, there would be a frequency reuse pattern, so another cell a few miles away would be using the same spectrum. So even then they are aimed somewhat down rather than at the horizon, as you said. But with LTE it's much more significant.