As we had produced fighting planes built around the Liberty motor, so, too, in the night-bombing class American invention, with the experience of several months of actual production behind it, was able to bring out an American bombing plane that promised to supersede all other types in existence. This machine was designed by Glen L. Martin in the fall of 1918. It was a night-bomber equipped with two Liberty 12-cylinder engines. The Martin spread of 75 feet gave it a carrying capacity comparable with that of the Handley-Page. Its speed of 118 miles an hour at ground level far exceeded that of either the Caproni or Handley-Page, and it was evident that its ceiling would be higher than that of the Caproni, the estimated ceiling of the Martin being 18,000 feet. The machine never reached the state of actual quantity production, but several experimental models were built and tested. Being built around its engine it reflected clean-cut principles of design, and its performances in the air were truly remarkable for a machine of its type. The following table shows the results of the preliminary tests of the Martin bomber:
| Test 1. | Test 2. | |
|---|---|---|
| Speed at ground level | 113.3 miles per hour | 118.8 miles per hour. |
| Climb to 6,500 feet | 10 minutes 45 seconds | 7 minutes. |
| Climb to 10,000 feet | 21 minutes 20 seconds | 14 minutes. |
| Climb to 15,000 feet | 30 minutes 30 seconds. | |
| Total weight | 9,663 pounds | 8,137 pounds. |
The total delivery of airplanes to the United States during the period of the war was 16,952. These came from the following sources: United States contractors, 11,754; France, 4,881; England, 258; Italy, 59.
| Apr. 30, 1918 | ██ 3 |
| May 31, 1918 | ██████████ 12 |
| June 30, 1918 | ██████████ 13 |
| July 31, 1918 | ███████████ 14 |
| Aug. 31, 1918 | █████████████████████ 26 |
| Sept. 30, 1918 | ██████████████████████████ 32 |
| Oct. 31, 1918 | ██████████████████████████████████ 43 |
| Nov. 11, 1918 | ████████████████████████████████████ 45 |
Estimates of aircraft strength on the front were always uncertain, due to variations in the estimates of the number of planes in a squadron. The standing of the United States in aeroplanes at the front is indicated in the estimate of the American Air Service as of November 11, 1918. The figures of this estimate are as follows:
| France | 3,000 |
| Great Britain | 2,100 |
| United States | 860 |
| Italy | 600 |
| Total | 6,560 |
These figures represent fighting planes equipped ready for service, but do not include replacement machines at the front or in depots or training machines in France.
| U. S. planes lost to enemy. | ████████████████████ 271 |
| Enemy planes lost to U. S. forces[29] | ████████████████████████████████████ 491 |
[29] Confirmed losses; in addition there were 354 unconfirmed.