Weight and performance issues plagued the U. S. Navy F-111B variant for TFX and would not be resolved to the Navy's satisfaction. The F-111 manufacturer General Dynamics partnered with Grumman on the Navy F-111B. With the F-111B program in distress, Grumman began studying improvements and alternatives. In 1966, the Navy awarded Grumman a contract to begin studying advanced fighter designs. Grumman narrowed down these designs to its 303 design. Vice Admiral Thomas F. Connolly, Deputy Chief of Naval Operations for Air Warfare, flew the developmental F-111A variant on a flight and discovered that it had difficulty going supersonic and had poor carrier landing characteristics. He later testified before Congress about his concerns against the official U. S. Department of the Navy position and, in May 1968, Congress stopped funding for the F-111B, allowing the Navy to pursue an answer tailored to its requirements. The name "Tomcat" was partially chosen to pay tribute to Admiral Connolly, as the nickname "Tom's Cat" had already been widely used by the manufacturer, although the name also followed the Grumman tradition of naming its fighter aircraft after felines.