Ultralight flight time does not count towards unfreezing ATPL as ultralights are considered as recreational aircraft and the flight time logged in them does not count towards any professional pilot certification requirements. Only flight time logged in a certified aircraft, such as a single or multi-engine airplane, can be counted towards the requirements for unfreezing an ATPL. It is important to consult with your aviation authority or a qualified flight instructor to determine the specific requirements for unfreezing an ATPL in your country or region.