I think I've just solved the entire mystery
The USS Nimitz incident with David Favour apparently occurred on Nov 14th 2004, around 100 miles roughly off the coast of San Diego.
That same week, NASA were testing the X43 Scramjet which can do Mach 10, and it launched from a B52 and accelerated to around 110000 feet, until it splash lands into the Pacific ocean, which is in roughly the same area as the Nimitz and it's battlegroup were, somewhere off the west cost of the US, certainly within distance of the jets. It wasn't recovered.
The times and dates don't match up exactly, but it does line up with the sort of thing we're talking about - a white object which moves at incredible speeds, being tested roughly within the same area, roughly around the same time David Favour saw some 'stuff' give or take a couple of days.
Throw in a few inconstancies, perhaps some misinterpretations and some abnormal instrumental readings (might be expected from an object traveling at Mach 10) and miscommunication between the people doing the tests and the Navy, to me it seems like quite a plausible and reasonable explanation. Lets also not forget, that David Favour might have spun his story a little to gain attention, although I can't prove that - it's not such a great leap.
https://www.space.com/536-nasa-scramjet-soars-7-000-mph.html
The test document is also quite interesting;
https://web.archive.org/web/2011072...org/Participate/Uploads/AIAA_DL_McClinton.pdf
It also makes sense, that NASA could have been made to keep the test a secret from the Navy; What better way to test the systems and crews of a carrier battlegroup, than to troll them with an object traveling at Mach 10, that they've seen before, during drills.
You'd get maximum millage out of the test, and you'd get to see whether the Aegis Radar would see it, how the F18s reacted to it, could they track it, etc. It's a brilliant test.