Anyone use molicel p42a batteries for their packs? How do these compare to 18650 as battery packs?

The molicel claims 4200mah, so if I made a 4s pack would get better flight times than say 1500mah 4s Lipo? Or more time than a 2000mah?

I don’t fully understand the dynamics of these li-ion as I have zero flight time with them.

All info welcome.

p42 are 21700 cells which are larger and heavier than 18650 (21mm diameter x 70.0mm height vs 18 x 65.0). They weigh more, typically close to 70g vs 50g for 18650, but offer more capacity and higher discharge rate.
Liion cells have higher energy density than typical lipos (more mah/g) but have much lower discharge rates (like a low discharge lipo used for your goggles or radio). 4x21700 cell pack will weigh close to 280g compared to a 4S 1500mah lipo is only 180g. If your drone can fly with a 280g battery and draw less than the rated CDR of the cell, you could use that battery, but how much longer flight time you would get compared to a lighter weight low discharge lipo would depend on your setup.

I fly them in a 6S2P configuration. They've got impressive capacity, but if you want acro it's going to be like flying a brick. You'll need to boost your PID tune and limit your throttle to use them well at all. They're also terribly expensive unless you're assembling the packs yourself.