Taliban fighters watched the last US planes disappear into the sky over Afghanistan around midnight Monday local time and then fired their guns into the air, celebrating victory after a 20-year insurgency that drove the world's most powerful military out of one of the poorest countries. The departure of the US cargo planes marked the end of a massive airlift in which tens of thousands of people fled Afghanistan, fearful of the return of Taliban rule after the militants took over most of the country and rolled into the capital earlier this month.