More than two-dozen lawmakers have signed a bipartisan letter urging the Defense Department to continue funding its adaptive propulsion efforts heading into the next budget cycle. Still circulating on Capitol Hill, the yet-to-be delivered letter addressed to Defense Secretary Lloyd Austin underscores the need to deliver the next-generation engine technology “as quickly as possible” to the military services’ fighter fleets. “If we do not continue to pursue advanced propulsion systems for our fighter aircraft, we risk opening the door for...