This is discussing the use of aviation gas in light aircraft. It is a tiny market compared with kerosine as used by jet aircraft. I am amazed that lead is still permitted at all - high octane lead free petrol has been available in the UK for decades. It can only be a price issue. I'm sure a light aircraft operator would accept a 25% reduction in range if the option is not flying at all.

The article states they use 1.7 million gallons per day of leaded fuel for aircraft, as opposed to 40 million gallons per day of jet fuel being used.