Question: what is the largest plane in the us air force
[{'answer': 'Lockheed C - 5 Galaxy'}, {'provenance': [{'wikipedia_id': '160434', 'title': 'Lockheed C-5 Galaxy', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 561, 'bleu_score': 0.7729816681753381, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 1222289614226121142}, 'section': 'Section::::Abstract.'}]}]