It is entirely possible they were just chatting a bit and meant "This thing would fly better in a dense atmosphere [than other ships]"... without any implication intended that it is actually being worked on.
May be (or rather, is very likely) that we'll just have to see if there was anything to it or not. But yeah, I cannot say I ever noticed any difference to the flight model in the tenuous atmospheres, which is probably why we got them in Odyssey. Hardly any need to change the flight model for them or add turbulence effects at higher altitudes*.
*Though one could argue they kind of exist with the Maelstrom clouds around (active/recently destroyed) Titans, where your ship gets kicked around. And maybe the storm Lagrange clouds? I've yet to come across one of those, though.