2 Engines on the Tail

There are two kinds of jets with their engines on the tail: regular jets and regional jets. Regional jets such as the Canadair Regional Jet (CRJ) and Embraer Regional Jet (ERJ) can only seat 50 or 70 passengers and get their name because their short distance range only allows them to operate within a certain region of the country. The regular size jets are the Douglas DC-9, McDonnell-Douglas MD-80 & MD-90, and Boeing 717 which are all extremely similar and based on the same design. Place your mouse over the red links below to see the illustration highlighted.



  • The DC-9 was one of the most popular aircraft built. Douglas built 976 of them between 1965 and 1980. Today there are less than 60 in service worldwide, mostly with small charter & freight operators.
  • The MD-80 is actually a generic name for the DC-9-81 and subsequent models MD-82, MD-83, MD-87,and MD-88. The MD-80 model continued where the DC-9 had left off and remained in production until the last order was delivered to American Airlines on December 28, 1999. Delta and American Airlines are the two largest operators of MD-80 in the world.
  • The MD-90 was built from 1994 until 1999, about 134 in all. Only Delta operates these today.
  • Boeing’s 717 program began development as the “MD-95” and entered service in 1999. Production ended in 2006.
  • Bombardier of Canada began producing the Canadair Regional Jet in 1992 and it is in production today. Over 1,700 have been produced so far. Most of the regional airlines in America use the CRJ, including Expressjet, Comair, and Skywest.
  • The Embraer Regional Jet began production in 1996 and is in production today. Expressjet and American Eagle are the two largest operators in this country.


Douglas DC-9
There are 5 different versions of the DC-9 and all differ in length. What sets the DC-9 apart from some MD-80s and all MD-90 and 717 models is the pointed shape of the tailcone.

The DC9 has 2 baggage compartment doors on the lower right side of the fuselage.

McDonnell-Douglas DC-9

McDonnell-Douglas MD-80
The MD-80 series can be recognized by the wedge shape of its tailcone.

Also, all MD-80 & MD-90 aircraft have small horizontal fins on either side of the fuselage under the cockpit (not shown in the illustration) which are called “strakes”. This helps improve aerodynamic stability.

McDonnell-Douglas MD-80

McDonnell-Douglas MD-90
The main difference in the MD-90 is its engines – larger and more tapered appearance than the earlier models. DC-9 and MD-80 aircraft are powered by Pratt & Whitney while these MD-90 engines are the IAE V2500, the most powerful engine to be mounted to the tail of an aircraft. All MD80 & MD90 aircraft have 3 baggage compartment doors on the lower right of the fuselage and the MD-90 is the longest of all these jets.
McDonnell-Douglas MD-90

Boeing 717
The Boeing 717’s engines are longer than an MD-90 and much larger than an MD-80/DC-9. The engines are made by BMW/Rolls-Royce. On most 717s, there will be a title “Boeing 717” either on the front near the door or on the engine cover so it is pretty obvious which is the 717.
Boeing 717

Canadair Regional Jet (CRJ)
The CRJ & ERJ are much smaller than any of the jets above and can be found at most airports in America today. The most obvious difference is that all CRJs have wingtip extensions called “winglets” while only one ERJ model has them – the 145XR version, flown by United Express.
Canadair Regional Jet

Embraer Regional Jet (ERJ)
The ERJ has a few features that set it apart from a CRJ. The nose is longer and more pointed; the tailcone is pointed (that’s actually the Auxiliary Power Unit exhaust); and the engines are longer.
Embraer Regional Jet (ERJ)



MD80 Seat Map

The cabins of the DC-9/MD-80/MD-90 and 717 aircraft are similar but there are a couple of major differences.

The DC-9 and 717 have one galley in the front and two lavatories at the rear. The MD-80/MD-90 have two galleys, front and rear as shown in the seat map to the left. The rear galley is 3 rows up from the back and there is a door, which you can see in the illustration above.

The seating configuration is either 2×3 or 3×2 (MD-88 shown in the illustration). EXCEPTION: the MD-87 only is configured like a DC9 except that the row over the wing where the exit is only has one seat on the left and two on the right.

In all of these aircraft, the last three rows will not have a window view because it is blocked by the jet engine.


Seating maps are shown for the Canadair & Embraer Regional Jets below.

The CRJ (left) has two across seating, while the ERJ (right) has one left, two right seating. There are a few variants of the CRJ model with a capacity of 50 or 70 passengers; the CRJ-900 model has a first-class seat secion.

Both have one galley (G) and lavatory (L) as shown, but the CRJ-900 model adds an extra for the first class passengers.

CRJ Seat Map
ERJ Seat Map


Mcdonnell-Douglas DC-9

Click for photos of DC-9 aircraft

McDonnell-Douglas MD-80

Click for photos of MD-80 & MD-90 aircraft

Boeing 717

Click for photos of Boeing 717 aircraft

Bombardier CRJ

Click for photos of Bombardier CRJ aircraft

Embraer ERJ

Click for photos of Embraer ERJ aircraft

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