FWIW, I have a few thousand hours flying jet fighters and have hit rather large birds at high speed (me, not them), and have been hit by rather large caliber bullets (I assume also at high speed). From the two videos, taken at two locations, I cannot positively id a drone. What is described as a sudden altitude change in the second video doesn't look like anything in the first video, though it's mostly blocked by the…
would a strike directly on the prop possibly cause a stall or some other force to move the fighter that far out of position, or change course that drastically? I'm curious given the distinct differences between piston engine and jet engine planes.
While the prop is, uh, properly a wing, and technically hitting something with it would interrupt the airflow, they're quite strong and would likely just destroy the object, slightly damaging the prop. If it did damage it beyond usability, it'd been way more obvious in the video and with the prop breaking off.
If you're talking about the aircraft stalling, then it's unlikely as we don't see that significant of a movement in the brief second of video. Under g-load (an "accelerated stall") the buffer between the onset of the stall and the stall itself is decreased, and as I said elsewhere that while I have no familiarity with the handling characteristics of that aircraft, there's simply doesn't look like enough time for a stall to develop between when the aircraft supposedly hit a drone and for-sure hit the other aircraft. And from what I could see, the movement doesn't at all look like a stall, and from the moment I saw the two aircraft in the video you can see the intercept occurring - that's likely harder for the unfamiliar to see being unfamiliar with the concept of two disparate turning circles crossing at a point in the future, differing because of bank angle (one or even both "circles - i.e. vectors - could even be straight lines) and because of differing speeds.
From the limited videos I've seen, one pilot could not, or simply did not, see the other aircraft, either because of the bank angle blocking the view or not realizing the aircraft was there and being focused elsewhere (such as the aircraft in from of them) and simply ran into the other aircraft. How they got into that position is the difficult investigation, and Juan's YouTube video pointed out that the sudden airborne airboss directive was to cross flight paths, when they didn't brief such and rather unlikely had ever practiced such, and may not have even realized such.