I've never seen or heard of Jet property being sold in the market (not that I've been wandering Bhendi Bazaar in search of Bulgari pouches). Of course, that doesn't mean it doesn't happen.
I am inclined to believe though that this phenomenon, if it exists at all, is not nearly as prevalent at Jet as it is at Air India. Jet are all about cutting costs (at any cost) and they seem to have changed the provisioning itself, which means no kits, fewer meals, pillows etc.
AI, on the, other hand, have no need to cut costs. And they seem to love their flab.
And speaking of flab, I'd expect there to be a holy riot if the AI employees' constitutional right to steal from the taxpayers was curbed in any way.