 In the US, the 1954 interceptor was well underway, and would ultimately introduce the Convair F-106 Delta Dart, an aircraft with many similarities to the Arrow.More advanced designs were also being considered, notably the Mach 3 Republic XF-103, and by the time the Arrow was flying, the much more advanced North American XF-108.Both of these programs were cancelled during the mock-up stage, as it was believed the need for a manned interceptor of very high-performance simply did not exist as the Soviets were clearly moving their strategic force to ICBMs.