The term 'Australian Flightless Bird' can be summarized by two crossword solutions: EMU (3 letters) and CASSOWARY (9 letters). The EMU is the largest bird native to Australia and the second-largest extant bird in the world after the Ostrich. It is a flightless bird with brown feathers, long legs, and a long neck. The CASSOWARY is a large, flightless bird native to the tropical rainforests of New Guinea, nearby islands, and northeastern Australia. It has a distinctive bright blue neck and head, and its body is covered in black feathers. Both the EMU and the CASSOWARY are important species in the Australian ecosystem.