It allows the fuel to withstand higher pressures without detonating in an uncontrolled manner. This is important in aircraft engines, which run at a significant

It allows the fuel to withstand higher pressures without detonating in an uncontrolled manner. This is important in aircraft engines, which run at a significant fraction of their maximum power output for most of their working lives. People have been looking for alternatives for a long time, but it's difficult because leaded aviation gasoline is not a very large market, and there are substantial regulatory obstacles.