article_snippet.sent: The smallest are starters, which extend up to a  altitude of 12 to 19 miles (20 to 30km).
article_snippet.sent: Next are jets, which extend 25 to 31 miles (40 to 50km), and the last are gigantic jets, which reach 44 to 56 miles (70 to 90km).
article_snippet.sent: The smallest are starters, which extend up to a maximum altitude of 12 to 19 miles (20 to 30km).
article_snippet.sent: Next are jets, which extend 25 to 31 miles (40 to 50km), and the last are gigantic jets, which reach 44 to 56 miles (70 to 90km).
article_snippet.sent: Starters extend up to an altitude of 19 miles (30km), jets extend to 31 miles (50km), and the gigantic jets reach up to 56 miles (90km).