This 19% stake seems like it would help jetBlue from being absorbed by Delta or American [mostly a fat chance unless you get some banks/funds involved like TPG etc]. Lufthansa can also get some Airbus planes at a discount through jetBlue.

Plus, LH might be able to provide B6 with some capital to buy an airline like Spirit or perhaps Frontier. Spirit would be perhaps the best and maybe jetBlue could swap those A319's for some A320's.

As most people say, a codeshare would seem likely.