Bombardier Global series

Similar in appearance, but has more, smaller cabin windows and different style cockpit windows.

Canadair Regional Jet 700

Similar in appearance, but has more, smaller cabin windows and different style cockpit windows.

Grumman G.159 Gulfstream I

This may seem a strange entrance here at first, but leave out the prop engines, tail and wings and it is easy to mix up the G-I and G-II. The wings are placed more aft on the G-II than on the G-I.

After Gulftream invented the IIB the company Aviation Partners designed its own winglets for the Gulfstream II. Compared to the winglets of the IIB the transition between the wings and the winglets is curved.

The Gulfstream IITT is the only Gulfstream with tip tanks, so it is easy to recognise. For the rest it is the same as the standard G-II.

Starting with the Gulfstream III the Gulfstream jets have a more streamlined cockpit with four curved windows and standard winglets. It also has five cabin windows, so the cockpit windows are the way to distinguish it from G-II variants.

The Gulfstream III is known by the US forces as the C-20A, C-20B, C-20C, C-20D and C‑20E.

This is a stretched G-III with wider diameter Rolls Royce Tay engines instead of the Rolls Royce Spey engines. Has six cabin windows on each side. The G-IVSP is an enhanced G-IV, but it cannot be distinguished from the G-IV externally. When Gulfstream introduced new marketing designations the Gulfstream IVSP became the G400. The G300 has a smaller range and less standard options. Both are externally not different from the G-IV and G‑IVSP. Note that the thrust reversers are normally metallic, but sometimes they are painted to make the aircraft look like a G450!

Military versions of the G-IV are designated C‑20F, C‑20G and C-20H by USAF, US Army and US Navy, Tp102 and S102 by the Swedish forces and U-4 in Japan.

The G450 is a slightly extended G400 with the nose (actually cockpit) of the G550. So it is longer, but this is only visible when you see a G-IV and G450 side-by-side. The G450 can especially be distinguished from the other G-IV versions by the engine nacelles, with a different type of thrust reversers: it has no fairings on the outside compared to the G-IV which has clearly visible fairings for the reversers. Note that the normally metallic thrust reversers and fairings of the G-IV can be painted to make the aircraft look like a G450! See photo above.

Unfortunately Gulfstream pulls the same trick with the G450 as with the G400: there is a G350, which looks the same, but it has a smaller range and less standard options. There is one external feature which can tell you that you have a G350 in front of you: the absence of the EVS camera below the nose, which is standard on the G450 but optional on the G350.

The marketing name G400 is used for a second time on a three metre shorter version of the G500. It has same design characteristics as the other family members: it has its new cockpit windows, winglets under 45 degrees compared to the wing, lower landing gear when on the ground, etc. The key recognition point are the five large oval cabin windows on each side.

A lengthened G-IV, but still with six windows on each side. Is mainly identified by the MD‑80-like tail, the more streamlined engine nacelles without external fairings for thrust reversers and the large space between the cabin door and the first cabin window.

C-37A is the American military designation of the G-V. The Israeli special mission variant is locally named Nachshon Shavit.

This was the shortest version of the based on the G650, until the launch of the even shorter G400. Like the G600 it has most often seven cabin windows on each side, but sometimes only six. To recognise it from the G600 you have to look at the distance between the main cabin door and the first window: this is larger at the G600 than the G500. For the rest it resembles its larger sibling: it has its new cockpit windows, winglets under 45 degrees compared to the wing, lower landing gear when on the ground, etc.

The G550 was originally going to be called G-VSP and is an improved version of the G-V. It is the last Gulfstream type based on the fuselage of the Gulfstream II (and even the Gulfstream I). Has seven on each side instead of six windows and therefore easy to distinguish from the G-V. The G500 is a G550 with a smaller range and less standard options. Like the G350/450, the G500/550 are externally the same, except that the EVS below the nose is optional on the G500.
Only a few G500s were sold. Therefore the marketing name was later reused on the new aircraft based on the G650.

The US forces designates the VIP version of the G550 as C-37B. 

The Gulfstream G550 proves to be a popular platform for special mission aircraft, as it is in used as an airborne early warning and control aircraft with the air forces of Israel, Singapore, Italy and USA. In Israel they are named Nahshon-Eitam or Oron (depending on application), while Italy designates then E-550A. The US Navy has a missile range support aircraft, named NC-37B. The EC-37B of the USAF has the same external shape.
All feature large bulbs in the nose, tailcone, the side of the fuselage (it has no cabin windows) and on top of the vertical stabiliser. 

The G600 fits between the smaller G500 and larger G650. You can recognise it by its seven cabin windows, although the smaller G500 often has seven cabin windows as well. To recognise the G600 from the G500 you have to look at the distance between the main cabin door and the first window: this is larger at the G600 than the G500. For the rest it looks like its siblings.

The largest Gulfstream jet ever built - until the announcement of the G700 - was the start of a new family. The G650 barely looks like the original, only the large oval cabin windows are a clear reminiscent of the earlier versions. For the rest it is a new aircraft:

• a larger diameter fuselage
• cockpit windows with a "swept" trailing edge of the aft windows
• a new, high aspect ratio wing
• winglets at an angle of 45 degrees with respect to the wings
• shorter main gear legs when on the ground
• horizontal stabilisers with some dihedral

Tthe G650 has eight cabin windows, one more than the G600 and one or two more than the G500. The G650ER is the extended range version, externally not different from the standard G650.

To be better able to compete head-on with the Bombardier Global 7500 the Gulfstream G650 was stretched to create the G700. The longer fuselage means room for more cain windows, ten on each side. Another clear recognition point compared to the G500/G600/G650 are the curved winglets.

The intended successor to the G650ER has the same fuselage, but then mated to the wings and tail of the G700. The G800 also has the same engines as the G700. From a recognition viewpoint this means that the eight cabin windows are no means to distinguish the G650 and G800. However, the slightly curved winglets are what to look for.