  Wireless Unmanned Aerial Vehicles (UAVs) were introduced in the world of 4th
generation networks (4G) as cellular users, and have attracted the interest of
the wireless community ever since. In~5G, UAVs operate also as flying Base
Stations providing service to ground users. They can also implement independent
off-the-grid UAV networks. In~6G networks, wireless UAVs will connect ground
users to in-orbit wireless infrastructure. As the design and prototyping of
wireless UAVs are on the rise, the time is ripe for introducing a more precise
definition of what is a wireless UAV. In doing so, we revise the major design
challenges in the prototyping of wireless UAVs for future 6G spectrum research.
We then introduce a new wireless UAV prototype that addresses these challenges.
The design of our wireless UAV prototype will be made public and freely
available to other researchers.
