The primary objective of the UEET ( Ultra - Efficient Engine Technology ) Program is to address two of the most critical propulsion issues : performance / efficiency and reduced emissions . High performance , low emissions engine systems will lead to significant improvement in local air quality , minimum impact on ozone depletion and level to an overall reduction in aviation contribution to global warming . The Materials and Structures for High Performance project will develop and demonstrate advanced high temperature materials to enable high - performance , high efficiency , and environmentally compatible propulsion systems .