Elon said they were in "very early" discussions with a "major OEM". I don't think this means Aptera or any other niche maker.
OTOH, very early discussions could be nothing more than a passing comment within a call about NACS adoption or something like that.
(By the way, remember how last year's news of Tesla's offer to make NACS a standard was widely derided and scoffed at around here- what a difference we see now.)
It could well be Ford, but again we don't know what "early discussions" really means. There's no reason for Jim Farley or Mary Barra to slam the door on Tesla when they themselves don't have any clear path.
And finally, news reports as well as Consumer Reports' analysis, of Tesla's relative position in the self-driving sweepstakes, are less than worthless. As always, if you know anything about it yourself, you know more than these people do. And that's before the distortion field of click-generating considerations is applied. We are way past the era of these publications and websites having any information authority.