Besides the SR-71/A-12, there were other stealth aircraft that preceded the F-117. The immediate predecessor was Lockheed's Have Blue[0] which was flying in the 70s. Related to Have Blue, there was also Senior Prom[1], which was apparently a scaled down unmanned "cruise missile" variant of Have Blue.

And beyond airplanes, the first stealth helicopters were developed in the late 60s to early 70s and saw limited service during Vietnam. Called The Quiet Ones[2], these helicopters were painted with radar absorbing paint and had several novel mechanisms to reduce their noise, making them stealthy not only to radar but also to ground observers. They were tested over Area 51 and apparently near LA as well, so it seems likely they may have spooked some civilians at one point or another. The infamous "black helicopter" conspiracies/stories started popping up in the 70s, which doesn't seem particularly coincidental when you consider that we now know the The Quiet Ones existed.

The original Quiet Ones are long gone, but it's evident they were replaced by newer stealth helicopters that we don't yet know the names of. We can be pretty sure of this because famously one crashed during the raid on bin Laden[3].

[0] https://en.wikipedia.org/wiki/Lockheed_Have_Blue

[1] https://en.wikipedia.org/wiki/Lockheed_Senior_Prom

[2] https://en.wikipedia.org/wiki/The_Vinh_wiretap#Planning_and_...

[3] https://en.wikipedia.org/wiki/Death_of_Osama_bin_Laden#Helic...