The Australian is reporting that JQ is touting 3 788s for sale. Apparently this is because they operate loss making routes thought to be SYD-HNL, MEL-HNL and OOL-NRT. Sale would mean 50 pilots would be made redundant or demoted so whether this is a serious sale campaign or an attempt to force pilots to agree to new EBA is debatable.
At the time they were brought into the Jetstar fleet, the 788s were touted as being a lot more cost effective than the A332s they replaced. The A332s mostly moved back to Qantas. Wouldn't the economics still apply?
From an operating cost, definitely; from a total cost of ownership perspective it is likely a 15 year old A332 is cheaper to operate than a 5 year old 787 due to depreciation and financing costs. I'm a cynic however and doubt very much that JQ have any intention to sell these planes. It is a fairly obvious "negotiation" tactic in relation to the JQ EBA.
717, 721/2, 732/3/4/5/7/8/9, 742/3/4, 752/3, 762/3, 772/E/W, 788/9, 300,310, 319,320/1, 332/3, 359, 388, DC9, DC10, F28, F100, 142,143, E75/90, CR2, D82/3/4, SF3, ATR