13,948 72-9 Billings i è 15,100 10,031 50°5 Missoula . 12,668 | 12,869 —I'6 Helena. . : . 77,988,000 19022 , : ; ; . | 33:6 | 233| 2+2 | 19:3 | 20:9 | 22:3 had suddenly come into general use for long distance pioneer flights