There's sooo many questions about all of it. I have watched almost the entire hearing and I totally agree that Americans have a right to know more answers about these phenomenon, but it will be hard to even know who to trust. The government does not really have a great track record for honesty and transparency; I mean our government is probably more honest than most, but that does not say very much. As for whistleblowers; its very possible they are just looking to get famous (and probably rich); after all, who is going to "prove" them wrong? I think its much more likely they are reporting what they have seen or been told but there is no reason to assume aliens from another planet based on what I heard.
The logical and likely answer is human technology; ie drones, new ships, etc. Who really knows what other governments or even private companies are doing. Heck, one of the guys even said there are things going on in our own government off the record. We have all kinds of stuff going on with AI, Elon is working on brain chips with Neuralink (don't let me get started on that), private companies are working on stuff with little knowledge to others., etc. Some of these are likely natural phenomenon with others being actual crafts we just haven't seen yet.
I really don't see any reason to assume a ridiculous number of other impossibilites (time travel, worm hole travel, physics, etc) and improbabilities (any possible life is intelligent enough and knows we are here, is close enough to travel here, etc) all happened and, can therefore, assume it is alien activity. Even it it were somehow alien activity it doesn't make any sense. How can they have time travel and physics bending technology and yet can't keep their crafts from crashing, being detected by radar, or even from being visible at all ("cloaking")? Aliens are a fun story to think about but I think the answers are right here on Earth and come from Humans.