I'm new to this forum/topic but I saw David Fravor's recent appearance on the Lex Fridman podcast and have started reading up on the tic tac incident. I like Mick West's idea that Fravor's observations could be explained by the actual object he observed being around half the size and half the distance he thought it was and actually being fixed/moving slowly as opposed to "mirroring" as Fravor interpreted. The question I would have, and maybe this has already been addressed somewhere, is how to account for the observations of the people in the other plane, around 8,000 feet above. According to Fravor, they saw the object speed away and disappear at the same time he did, which is not what you would expect if the object was relatively fixed and they were 8,000 feet away. You would expect them to just continue observing the object.
I'm new here too. And I don't believe your question (among other questions regarding the Fravor-optical illusion theory) has been adequately addressed.
For a stationary object/optical illusion explanation to be plausible, it requires David Fravor to have ignored his flight speed, altitude, climb rate, heading and attitude indicator during what he described was a 5-minute engagement in which he's trying to gain a potential-energy advantage over an aerial target. It also requires that his WSO in the backseat do likewise. It also requires that the other pilot, thousands of feet above Fravor with eyes on both Fravor and the target, coincidentally experience a separate yet simultaneous optical illusion and ignore her flight instruments, etc. for the same duration. It also requires her WSO to do likewise. It also requires the veteran radar operator back at the USS Princeton to simultaneously track a false, moving target on his scope that is consistent, coincidentally, with the apparent movement caused by the optical illusion all the people in the air are allegedly experiencing. It also requires a stationary object to entirely and abruptly disappear from the view of all four eyewitnesses (and the scope of the radar operator) at the same time without moving, despite David Fravor saying he watched it depart at high speed. It also requires one to ignore the most consistent characteristics of the object across all testimony: that it accelerated rapidly and was capable of traveling at very high speed. It also requires one to ignore Fravor's testimony prior to engaging the target, when he describes the object as moving erratically and turning sharply.
I propose that the eyewitness's statements are more consistent with (and more simply explained by) a rapidly accelerating, fast moving object than a stationary one. I don't think it's whimsical to suggest that, based solely on eyewitness accounts, the object likely wasn't a balloon and that it likely moved quickly. Existing fast-moving military aircraft, for instance, are a better fit to the testimony than a balloon or other slow-moving object.
The good people here at Metabunk do tremendous work when it comes to image analysis, specifically the work done on the three Navy videos. In my opinion this David Fravor-balloon theory, based solely on eyewitness accounts, is not consistent with that work.