The proliferation of Uncrewed Aerial Vehicles (UAVs) in applications such as flying ad-hoc networks (FANETs), precision agriculture, disaster response, and future 6G integrated networks necessitates the development of accurate and robust Air-to-Air (A2A) wireless communication systems. While existing research has predominantly focused on Air-to-Ground (A2G) links, the A2A channel remains significantly under-characterized, especially in the sub- 6 GHz frequency bands critical for reliable data exchange. Current A2A models often oversimplify the channel, relying on static assumptions that neglect the profound impact of the UAVs' three-dimensional mobility and the physical characteristics of the aerial platforms themselves. This paper addresses this research gap by presenting a preliminary set of measurements for the 3.4 GHz A2A channel. We have developed a lightweight, reconfigurable, opensource channel sounder using USRP B210 Software-Defined Radios (SDRs) and a high-precision Global Navigation Satellite Systemdisciplined oscillator (GNSS-DO), deployed on two UAVs. We conducted a measurement campaign at the Aerial Experimentation and Research Platform for Advanced Wireless (AERPAW) Lake Wheeler testbed, an ideal, instrumented rural environment for UAV experimentation. The campaign featured a spherical flight trajectory around the second drone, designed to capture the dynamic channel characteristics during maneuvers, including circular orbits, various altitudes, and elevation angles. From these data, we present a thorough analysis of the fundamental channel characteristics. We extract and model the fading parameters from the channel measurements, including channel impulse response (CIR), and analyze their dependence on link geometry. We also characterize the fading statistics, providing insights into the RMS delay spread for A2A links in this environment. This foundational channel measurement dataset provides a more realistic and validated tool for the design, development, emulation, and performance evaluation of physical and MAC layer protocols for next-generation UAV communication networks.