Does The Drifting Classroom have a happy ending?
For most of the characters the answer is left open ended. All but one member of the classroom are left in the distant future. They do find a source of clean water and those who are still alive have been working well together so perhaps they can at least survive there. Yu is a small boy who does get to return home. He is adorably reunited with his tricycle and that's a happy enough ending for me.