Question: The Messerschmitt 109TL was an alternative design proposed as a backup for a fighter version of a plane nicknamed what? 
Sentence (from "Messerschmitt Bf 109TL"): The Messerschmitt 109TL was a turbojet fighter designed in 1943 by the Messerschmitt company for the "Luftwaffe" during World War II.
Relevant evidence: Yes