You are correct in that you can’t isolate specific products to the exclusion of the other by-products. However, if you have a refinery that is dedicated to airline fuel, then I think you can customize the equipment towards that purpose and minimize the other by-products.
In my province, we have a plant that produces plastic pellets from all the waste fuels that the refineries otherwise burn off.
ridesthemiles I think you are right. In low travelling periods they can probably have controls and equipment in place to increase what is either more profitable or what is more in demand. I’m not a petroleum engineer, but understand a little of it.