I'm equally amused by Chris Lehto's UAP channel & Mick West UAP debunking channel.
I looked into one of the recent Chris Lehto videos, by an Australian who shared his video of an event.
It sound's like a drone to me - I hear beat interference, indicating two or more sound sources with similar very close frequency
I made a video showing the spectrogram of the audio, focusing on the region from around 300-400 Hz.
It looks to me there are two sound sources, since at the perceived pitch change at the 0:32 timestamp I see two overtones keeping distance that decreases with the perceived pitch decrease, while another overtone increases the distance from these.
Also, the overtone distance indicates a missing fundamental of 10Hz, decreased to around 4-5 Hz at the 0:32s timestamp. Drone engine operating at 4-10 RPM sounds like a possibility.
The original Chris Lehto video linked in the description; the UAP video is in the start of Chris Lehtos video. (I ripped the audio from a Short video on Chris channel, but it seems gone now).
Audio LP-filtered:
Fun fact, I HP filtered the audio as well. The recording is in late evening. Can't say there's no normal night sounds, but I BP filtered something that sounds like a bird.
I'm no ornithologist, but checked it with an app that suggested "European Greenfinch", even if the confidence was low; though it sounds kind of similar.
Apparently, finches don't vocalize at night, so why do I hear that in this late evening UAP audio.
Here's my video on the suspected finch sounds: (Crickets or something in the first part, suspected finch in the later half, and also I refined and repeated that at the end of the video):