No jets use or have ever used leaded products. Jets run on Jet-A, which is a close relative of kerosene. It has never been leaded. The purpose of lead was to prevent cylinders from prematurely detonating ("knocking") in internal combustion engines. Jets do not have any cylinders to knock; the fuel burns continually in an open combustion chamber.
You may have been thinking of 100LL (100 Low Lead) fuel for piston engined planes. Many airports stopped selling 100LL in January of 2022. The FAA has approved a lead-free replacement in fuels like UL94 that are steadily replacing 100LL.
You may have been thinking of 100LL (100 Low Lead) fuel for piston engined planes. Many airports stopped selling 100LL in January of 2022. The FAA has approved a lead-free replacement in fuels like UL94 that are steadily replacing 100LL.