Essentially a refined and enlarged Model D, variants of the Model E made important steps in pioneering the development of seaplanes and flying boats in America. Like its predecessor, the Model E was an open-framework biplane with two-bay unstaggered wings of equal span. In landplane configuration, it was fitted with tricycle undercarriage, and as a seaplane with a large central pontoon and outriggers under the wings. Most examples of the Model E followed the pattern of the "headless" Model Ds, with elevators and horizontal stabilizer carried together in the cruciform tail unit. The large ailerons were mounted in the interplane gap, their span continuing past the wings themselves, and were controlled by a shoulder yoke. The Model E was designed and built as a two-seater, although in practice some of the lower-powered versions were converted to single-seaters.

The Model E achieved fame through examples purchased by the United States Navy. A Model E-8-75 floatplane became the Navy's first aircraft when purchased in June 1911 and received the designation A-1, as well as the nickname "Triad" since it could operate from the land and sea and in the air. Theodore Ellyson became the Navy's first pilot when he took off from Keuka Lake near Hammondsport, New York on 30 June. In all, the Navy was to purchase some 14 Model Es, designating their earliest examples from A-1 to A-4, then redesignating these together with new purchases in the AH-1 to AH-18 block of serials. These aircraft achieved a number of firsts for the Navy, including the first cross-country flight in a seaplane, a world seaplane altitude record of 900 ft (274 m) and a much later national seaplane altitude record of 6,200 ft (1,890 m), and significantly for later naval operations, the first catapult launch of a seaplane.

The aircraft originally designated A-2 had an especially interesting career. Purchased by the Navy in landplane configuration on 13 July 1911, it was converted into a floatplane the following June. In this configuration it set a seaplane flight endurance record of 6 hours 10 minutes on 6 October 1912. Later that month, it was extensively rebuilt along the lines of the Curtiss Tadpole hull, thus becoming the Navy's first flying boat. Later still, retractable wheels were added to create an amphibian that became known as the OWL (standing for "Over Water and Land"). This machine was redesignated E-1 and then AX-1 by the Navy and was finally destroyed on 27 November 1915.

In addition to their naval service, the type was operated by the Aeronautical Division, U.S. Signal Corps, which purchased two examples of the Model E-4 (Signal Corps numbers S.C. 6 and 8), built a third entirely from spare parts (S.C. 23), and later acquired one of the Navy's seaplanes (AH-8). Poor safety and reliability records of pusher aircraft led to all examples being grounded on February 24, 1914, although the AH-8 was flown briefly in 1928 following a refurbishment.

Variants

• Model E-4 - version with 40 hp (30 kW) four-cylinder engine
• Model E-8 - version with 60 hp (45 kW) vee-8 engine
• Model E-8-75 - version with 75 hp (56 kW) vee-8 engine