Thank you! I was tempted to post that in response to JimNTexas' original question. The biggest difference from a refinining standpoint is that Jet A has a slightly shorter carbon chain than diesel.
I don't know all of the additives that are put in each after refining but diesel isn't going to need the same amount of FSII as Jet A. And from reading others' posts, it appears that Jet A doesn't have as many lubricant additives as diesel. This article confirms additional lubricant additives in diesel fuel: http://www.ehow.com/facts_5808896_difference-jet-fuel-diesel-fuel_.html
Both Jet A and diesel can be refined from heavy or light crude.
The problem with heavy crude is that it has a longer carbon chain than light crude so that it requires more refining than light crude.
As to the wisdom of an airline acquiring a refinery, I'll defer to those in the oil industry. http://www.foxbusiness.com/industries/2012/04/06/is-refinery-ownership-key-to-airline-fuel-woes/
Jet fuel has lots of additives.. including things that are added to make it less likely to explode in a crash....http://www.youtube.com/watch?v=Y33N0raKZBo (test footage of fuel additive added)