The SPAD VII entered service for the French in 1916 and was the primary French fighter during 1916-1917. Designed by Louis Bechereau and Marc Birkigt, this fighter aircraft was fast, maneuverable and able to absorb a considerable amount of damage. However, it only carried one machine gun which left it somewhat under-gunned when dealing with the two gun designs flown by the Germans. The American volunteer squadron Lafayette Escadrille flew SPAD VII until the end of World War I.
The Nieuport 28 was less sturdy and less favored by French pilots, and was the first plane flown by American Expeditionary Force pilots. The upper wing had a tendency to shred in steep dives and the design was generally considered obsolete by the spring of 1918, causing the American military to understand that if it didn’t have it’s own up-to-date designs, then American pilots would be stuck in the cast-off obsolete designs of its allies.
For more information about these planes and others see: http://www.nationalmuseum.af.mil/exhibits/