I listened to the Guacha stream again and Ayi added to the conversation after regarding the NGAD demonstrators. He's opinion was the NGAD demonstrators must have been very preliminary. Something like a modern day F-15 ACTIVE:
Were they took an existing plane and changed its planform to test out aspects of 6th gen aerodynamics.
His reasoning was:
1. If the demonstrator were more mature and visually looked distinctive enough to pass for danger dorito 6th gen mental image that people are expecting then they would have shown it off by now, if not before Chinese 6th gen maiden flight.
2. CAC probably made their estimation of maiden flight by mid 2025 based on the assumption that the NGAD demonstrator was of similar maturity to their own demonstrator, and then they extrapolated the timeline and arrived at the mid 2025 date. The fact that the Americans haven't flew their 6th gen means either they're incompetent (which you should not assume) or the demonstrator was further away from actual 6th gen than CAC's own demonstrator.
