Assertion: winged aircraft | /r/HasProperty | invented
Facets:
Source sentences:
text: Although balloons do not generally meet today's definition of a UAV, the concept was strong enough that once winged aircraft had been invented, the effort to fly them unmanned for military purposes was not far behind.
text: ’s definition of a UAV, the concept was strong enough that once winged aircraft had been invented, the concept was still alive and kicking and would soon be implemented once again.