Both the Dash-8 (top right) and ATR (bottom right) have their wings on the top of the fuselage. The major difference is that on the Dash-8, the landing gear retract up into a space under the engine housing. The ATR’s landing gear retracts up into the bottom of the fuselage.
There have been 4 different versions of the Dash-8 built since its introduction and all differ in length, passenger capacity, and engines. The latest version shown here, in production since 2000, is the longest and nearly 20 feet longer than an ATR.
Besides the landing gear, an ATR can be distinguished from a Dash-8 by its tailcone, which is longer and pointed. The ATR comes in two versions with several sub-types each: the ATR-42 and ATR-72, which is 14 feet longer. The ATR-72 can carry up to 78 passengers 825 nautical miles while a Dash-8 can carry up to 90 passengers 1,100 nautical miles.