Legislation can change.
Solid electrolyte batteries don't burn/explode, so it's safe to transport them on planes (or any other other traditional method for that matter) regardless of the capacity.

if in airplanes ban batteries larger than 99Wh with the current 250-300Wh/kg, how are they going to produce higher capacity batteries in laptops? But this limitation does not prevent us from increasing the energy density in smartphones, right? Where 99Wh is very far away. So where are the improvements in smartphone batteries or is there a clear cahoot among manufacturers not to provide higher capacity batteries to customers if there is real progress in energy density and amount of recharge cycles?

I've been hearing this for 20 years in 100,500 applications from all sorts of startups, and then they forget about them. But perhaps the owners of the next startup will attract money from the next foolish investors and live on it very well for many years. =)

And we are still sitting with dull batteries for 300-700 cycles (at best, up to a 75% drop in capacity) and a maximum of 250Wh/kg on average.

Where are all these promises of 5-10-15-20 years ago? Even promises made 5-7 years ago should already be implemented in ready-made manufacturing technology and massively used in production if they really provided a technological breakthrough...

I'll just leave this here: Ilika