| 1 | us air mail service | | | | | | | 3 | 1.66% |
| 2 | of the us air | | | | | | | 2 | 1.10% |
| 3 | home history index air | | | | | | | 1 | 0.55% |
| 4 | wind snow and sleet | | | | | | | 1 | 0.55% |
| 5 | snow and sleet to | | | | | | | 1 | 0.55% |
| 6 | pioneer roundtheclock airmail service | | | | | | | 1 | 0.55% |
| 7 | roundtheclock airmail service along | | | | | | | 1 | 0.55% |
| 8 | airmail service along the | | | | | | | 1 | 0.55% |
| 9 | service along the worlds | | | | | | | 1 | 0.55% |
| 10 | along the worlds longest | | | | | | | 1 | 0.55% |
| 11 | they battered wind snow | | | | | | | 1 | 0.55% |
| 12 | the worlds longest air | | | | | | | 1 | 0.55% |
| 13 | route the u s | | | | | | | 1 | 0.55% |
| 14 | the u s transcontinental | | | | | | | 1 | 0.55% |
| 15 | u s transcontinental in | | | | | | | 1 | 0.55% |
| 16 | s transcontinental in the | | | | | | | 1 | 0.55% |
| 17 | transcontinental in the process | | | | | | | 1 | 0.55% |
| 18 | battered wind snow and | | | | | | | 1 | 0.55% |
| 19 | havillands they battered wind | | | | | | | 1 | 0.55% |
| 20 | the process thirtyfour pilots | | | | | | | 1 | 0.55% |
| 21 | unsung heroes of early | | | | | | | 1 | 0.55% |
| 22 | 1918 until 1927 air | | | | | | | 1 | 0.55% |
| 23 | until 1927 air mail | | | | | | | 1 | 0.55% |
| 24 | 1927 air mail service | | | | | | | 1 | 0.55% |
| 25 | air mail service pilots | | | | | | | 1 | 0.55% |
| 26 | are the unsung heroes | | | | | | | 1 | 0.55% |
| 27 | the unsung heroes of | | | | | | | 1 | 0.55% |
| 28 | heroes of early aviation | | | | | | | 1 | 0.55% |
| 29 | de havillands they battered | | | | | | | 1 | 0.55% |
| 30 | history index air mail | | | | | | | 1 | 0.55% |
| 31 | early aviation in their | | | | | | | 1 | 0.55% |
| 32 | aviation in their frial | | | | | | | 1 | 0.55% |
| 33 | in their frial curtiss | | | | | | | 1 | 0.55% |
| 34 | jennies and postwar de | | | | | | | 1 | 0.55% |
| 35 | and postwar de havillands | | | | | | | 1 | 0.55% |
| 36 | postwar de havillands they | | | | | | | 1 | 0.55% |
| 37 | in the process thirtyfour | | | | | | | 1 | 0.55% |
| 38 | their lives through profiles | | | | | | | 1 | 0.55% |
| 39 | process thirtyfour pilots lost | | | | | | | 1 | 0.55% |
| 40 | 1999 nancy allison wright | | | | | | | 1 | 0.55% |