Astra 1125 vs Astra SP vs SPX: Key Differences Explained

Three business jets. One family tree. And a handful of small changes that added up to a very different airplane by the end. The Astra 1125, the Astra SP, and the Astra SPX all grew from the same roots, yet each one flew a little farther, climbed a little higher, and felt a bit more modern than the one before it.

Israel Aerospace Industries built this jet as a step up from its older Westwind. Over about a decade, the design kept getting better. Stronger engines showed up. Winglets appeared on the wingtips. The cockpit went digital. If you have ever tried to line up the Astra 1125 vs Astra SP vs SPX, you know the names look almost identical on paper, but the airplanes underneath them are not.

The gap between the first Astra and the last one is far wider than a single letter at the end of its name lets on.

Key Takeaways

The main difference between the Astra 1125, Astra SP, and Astra SPX comes down to engines, wings, and avionics. The 1125 was the original. The SP kept the same basic shape but added a nicer cabin and a modern glass cockpit. The SPX brought stronger engines, winglets, and better range, and it later became the Gulfstream G100. Each model built on the one before it, so the newest version is the fastest and flies the farthest.

If you ever find yourself sizing up one of these jets on the used market, Flying411 is a handy place to see how Astra models stack up against other aircraft, all in one spot.

Meet the IAI Astra Family

Before we pull the three models apart, it helps to know where they came from. The IAI Astra business jet did not appear out of nowhere. It grew out of an older design that had already been flying for years.

Israel Aerospace Industries, often shortened to IAI, is a large aerospace company based in Israel. Back in the 1960s, it took over a jet program that had started in the United States as the Aero Commander Jet Commander. IAI reworked that airplane into the Westwind, a small business jet with its wing mounted in the middle of the fuselage and two engines tucked near the tail.

By the late 1970s, IAI wanted something better. The result was the Astra. It kept a few familiar pieces from the Westwind, including the tail and the engine housings, but almost everything else was new.

The single biggest change was the wing. On the Westwind, the wing ran through the middle of the cabin. On the Astra, the wing was moved down low on the body. That one move freed up cabin space and gave passengers more headroom.

Here is the short version of the family line:

• Jet Commander: the original American design from the 1960s
• Westwind: IAI's reworked version with mid-mounted wing and turbofan engines
• Astra 1125: a near clean-sheet redesign with a low wing
• Astra SP: a refined 1125 with a better cabin and glass cockpit
• Astra SPX: the strongest Astra, later renamed the Gulfstream G100
• Gulfstream G150: a wider, updated follow-on built after the SPX era

Good to Know: The Astra shares its DNA with the Westwind, and the two can look alike from a distance. The easiest tell is the wing. The Westwind carries its wing in the middle of the fuselage, while every Astra sits on a low-mounted wing.

The Astra prototype first took to the air in the mid-1980s. The airplane earned its FAA certification in 1985, and the first customers received their jets in 1986. From there, the design kept evolving for the next decade and beyond.

A Quick Look at Where It Fits

The Astra was built as a midsize business jet. That means it slots between small light jets and the big long-range machines. It could carry a small group of passengers across the country, take off from shorter runways than you might expect, and cruise at high speed.

Astra jets were never the top seller in their class. They were a bit of a niche pick, known more among pilots and operators who valued speed and short-field ability than among the general public. That reputation would follow all three versions through their production runs.

Astra 1125: The Original Midsize Jet

The Astra 1125 is where the story starts. This was the first of the line, and it set the shape and feel that the later models would build on.

Under the skin, the 1125 carried two TFE731 engines built by Garrett, a company later folded into Honeywell. Each engine produced roughly 3,650 pounds of thrust. The engines sat high and far back on the fuselage, near the tail, which helped keep engine noise out of the cabin.

The airplane had a few standout traits for its time:

• A moderately swept low wing that helped it fly faster than the older Westwind
• Leading-edge slats that gave it solid short-field performance
• A tall cabin with near-vertical sidewalls, often called a "square oval" shape
• The ability to lift a full load off runways of modest length

The cabin was a real selling point in a quiet way. Because the wing no longer ran through the middle of the body, headroom went up noticeably compared to the Westwind. The straight-up sidewalls also gave passengers more shoulder and elbow room than a rounded tube would.

Fun Fact: The Astra's cabin is widely known for its "square oval" cross-section. The nearly vertical walls trade a little outside sleekness for real elbow room inside, which is why some passengers felt roomier in an Astra than in wider-looking rivals.

Still, the 1125 was an early-1980s design, and it showed in a few areas. The cockpit used the instrument technology of its day. The range, while respectable, sat around 2,700 nautical miles in a favorable setup. And the cabin, though tall, was narrower than many competing midsize jets.

None of that made the 1125 a bad airplane. It made it a first draft. IAI clearly saw room to improve, and it did not wait long to start.

Astra SP: The Refined Middle Child

The Astra SP arrived around 1989 and replaced the original 1125 on the production line. The "SP" is often read as "special performance." If the 1125 was the first draft, the SP was the polished rewrite.

Here is the interesting part. From the outside, the SP looked almost the same as the 1125. There were no dramatic new wings or wingtips to point at. The changes were mostly on the inside and in the details.

The headline upgrades on the SP included:

• A revised, more comfortable cabin interior
• An upgraded EFIS glass cockpit with electronic flight instrument displays
• A Collins digital autopilot
• Small aerodynamic refinements that nudged the range up a bit
• A modest bump in hot-and-high climb ability

That glass cockpit was the big deal. Swapping older gauges for electronic displays made the airplane feel current and gave crews cleaner, easier-to-read information up front. The aerodynamic tweaks were subtle, but they helped the SP fly a touch farther than the 1125 and even allowed certain takeoffs without deploying flaps.

Pro Tip: When you see an Astra listing that mentions an EFIS cockpit but no winglets, you are almost certainly looking at an SP rather than a 1125 or an SPX. The glass panel without the wingtips is a strong SP fingerprint.

The engines on the SP stayed close to the 1125's setup, using TFE731-3C units rated near 3,700 pounds of thrust each. So the SP was not a huge jump in raw power. It was a jump in refinement, comfort, and cockpit technology.

Production of the SP was fairly limited. Records commonly point to around 37 airframes built before the next version took over. That short run makes the SP the rarest of the three in day-to-day terms, since fewer were ever made.

Astra SPX: The Big Leap Forward

The Astra SPX is where the family took its largest single step. It first flew in August 1994 and reached customers in the mid-1990s. If the SP was a polish job, the SPX was a genuine upgrade you could feel in the air.

The SPX changed three things that matter most to how an airplane performs: the engines, the wings, and the cockpit.

Stronger engines. The SPX swapped in more powerful TFE731-40R turbofans, each producing around 4,250 pounds of thrust. That is a real bump over the roughly 3,700 pounds in the SP. On top of the extra muscle, these engines added digital electronic engine control, sometimes called FADEC or DEEC. In plain terms, setting thrust became a simple, precise move instead of a careful manual balancing act.

Winglets. This is the change you can spot from across the ramp. The SPX added small Astra SPX winglets at the wingtips. Winglets smooth out the airflow curling off the end of the wing, which cuts drag and helps with fuel efficiency and range. They are also the single clearest way to tell an SPX apart from the earlier models.

Modern avionics. Up front, the SPX came with a four-tube Pro Line 4 avionics suite from Collins. For the mid-1990s, this was a sharp, modern flight deck. It handled the job cleanly and kept the airplane competitive with newer designs.

Why It Matters: Winglets are not just for looks. By taming the swirling air at the wingtip, they help the SPX squeeze out more range and better efficiency from the same wing. That is a big reason the SPX flies noticeably farther than the SP on a full load.

The SPX also offered an optional auxiliary power unit, or APU. An APU provides electrical power and air conditioning on the ground without needing a power cart, which is a genuine comfort and convenience on hot ramps and remote fields.

Put all of that together and the SPX climbed higher, cruised fast at around Mach 0.82, and stretched its range toward the 3,000 nautical mile mark in the right configuration. It was widely regarded as one of the faster midsize jets of its era.

The SPX story does not end there, though. In 2001, Gulfstream acquired Galaxy Aerospace, the company that held the Astra type certificate. The following year, the SPX was rebranded as the Gulfstream G100. The airplane itself stayed essentially the same. The name and the support network changed. A stretched, wider follow-on called the G150 came later.

Astra 1125 vs Astra SP vs SPX: The Differences That Matter

Now for the heart of it. When people compare the Astra 1125 vs the SP vs the SPX, a lot of small spec lines get thrown around. Here are the differences that truly change how these jets fly, feel, and hold value. There are more than a few, so take them one at a time.

1. Engines and thrust. This is the clearest performance gap. The 1125 and SP both used TFE731-3 series engines in the 3,650 to 3,700 pound range. The SPX jumped to TFE731-40R engines near 4,250 pounds each. More thrust means better climb, better hot-and-high ability, and more confident performance overall.

2. Winglets and wingtips. The 1125 and SP have clean wingtips with no winglets. The SPX added winglets. This is the fastest visual way to sort an SPX from the two earlier models.

3. Engine control. The 1125 and SP set thrust manually. The SPX brought digital engine control, so pilots got smoother, more precise thrust handling with a simple lever movement.

4. Cockpit and avionics. The 1125 used the flight instruments of its day. The SP moved to an EFIS glass cockpit. The SPX went further with a four-tube Collins Pro Line 4 suite. Each step made the flight deck more capable and easier to fly.

5. Range. Range climbed with each version. The 1125 sat around 2,700 nautical miles. The SP added a little more thanks to aerodynamic tweaks. The SPX pushed toward the 3,000 nautical mile range in a favorable load, helped by its winglets and stronger engines.

6. Speed and ceiling. All three are quick for their class, cruising near Mach 0.82. The SPX, with its extra power, could climb higher and hold speed more comfortably at altitude than the earlier pair.

7. Cabin refinement. The basic cabin shape carried through all three, keeping that tall "square oval" feel. The SP improved the interior over the 1125, and the SPX refined it further while adding options like the APU.

8. Production and rarity. The SP had a short production run of roughly 37 airframes, making it the least common of the three. The SPX, later sold as the G100, saw a longer life and larger fleet. Combined Astra and G100 production came to somewhere around 145 airframes.

9. Later identity. The 1125 and SP stayed Astras their whole lives. The SPX lived a second life as the Gulfstream G100 and helped seed the later G150. So the SPX is the only one of the three you might see wearing a Gulfstream badge.

Heads Up: All three Astras share a cabin that is narrower than several midsize rivals. The tall sidewalls help it feel roomier than the width suggests, but tall passengers and larger groups should sit inside one before assuming it will feel as wide as the competition.

That is a lot of moving parts. The simplest way to hold it in your head is this: the SP fixed the cockpit and cabin, and the SPX fixed the performance.

Not sure what an Astra should cost before you start comparing variants? Flying411 lets you value your aircraft so you walk into the search with a realistic number in mind.

Side-by-Side Spec Comparison

Sometimes a single table says it faster than paragraphs can. Here is a rounded, at-a-glance look at the three variants. Treat the numbers as general guides, since exact figures shift with configuration, weight, and the source you read.

The pattern is easy to read once it is laid out. Every row either stays the same or improves as you move from left to right. That is the whole Astra story in one grid.

How to Tell Them Apart at a Glance

Say you are standing on a ramp and an Astra taxis by. Can you name the version before it parks? With a couple of quick checks, usually yes.

Start with the wingtips. This one clue does most of the work:

1. Winglets present? If yes, it is an SPX (or a G100, which is the same airframe). If no winglets, it is a 1125 or an SP.
2. No winglets, then check the cockpit. A modern glass EFIS panel points to an SP. Older instruments point to the original 1125.
3. Check the badge and paperwork. A Gulfstream G100 label confirms an SPX-generation airframe wearing its later name.

Quick Tip: Winglets first, cockpit second, badge third. Run those three checks in order and you can sort almost any Astra you meet, even from a distance.

Because these jets are somewhat uncommon, spotting one at all is a small treat for aviation fans. The Astra sits comfortably among the planes you rarely spot at a typical airport, so getting the variant right earns extra credit.

Which Astra Variant Is Right for You

If you are weighing one of these jets for purchase, the "best" version depends on what you value and what you are willing to spend to own and operate.

Here is a simple way to think it through:

• Tightest budget, lightest mission: An earlier 1125 can be the cheapest way into an Astra, but factor in older systems and a smaller support base.
• Want a modern cockpit without SPX pricing: The SP gives you the glass EFIS panel and a nicer cabin while staying below SPX money. Just remember it is the rarest, so listings are thin.
• Best all-around performance: The SPX is the clear pick for range, power, and avionics. It is also the version most likely to have solid parts and service support thanks to its Gulfstream G100 life.

Ownership costs matter as much as the sticker price. Older Astras can carry higher maintenance attention, and the fleet's smaller support network has long been a known tradeoff. Two areas deserve a close look on any Astra you consider:

• De-ice system. The Astra line used pneumatic de-ice boots on the leading edges, a design some pilots have criticized against heated leading edges.
• Auxiliary fuel and baggage. Long-range setups can eat into aft baggage space, so plan cargo and fuel needs together rather than separately.

Keep in Mind: With any older midsize jet, a thorough pre-purchase inspection is worth every dollar. Engine time, avionics status, and de-ice condition can swing the real cost of an Astra far more than the asking price alone.

A good broker or marketplace helps here, since you can line up several airframes and compare their true condition side by side rather than guessing from a single listing.

When you are ready to move from research to real listings, Flying411 connects buyers with aircraft sellers and certified maintenance shops so you can vet an Astra properly before you commit.

What Happened After the SPX

The Astra story did not stop when the SPX rolled off the line. The design kept living under new names.

After Gulfstream took over the type certificate, the SPX became the Gulfstream G100. Same airplane, new badge, new support structure. Then Gulfstream stretched and widened the concept into the G150, which offered a bigger cabin, oval windows, and updated systems. Some SPX-generation airframes even served in uniform, flying military support roles under a military designation.

So the SPX holds a special place among the three. It is both the peak of the pure Astra line and the bridge to everything that came after. If the 1125 opened the story and the SP tightened it up, the SPX is the version that carried the design into its next chapter.

That evolution is a reminder of how business jets quietly reinvent themselves over decades. Some airframes end up with surprising second lives and odd histories long after their first owners move on, and the Astra-to-Gulfstream path is a tidy example of a design that refused to fade away.

Ready to see what is out there right now? Browse current aircraft listings and services on Flying411 and start comparing Astra variants with confidence today.

Conclusion

The Astra 1125 vs Astra SP vs SPX question really comes down to three upgrades stacked on top of one shared design. The 1125 introduced the low-wing shape and roomy square-oval cabin. The SP kept that shape and modernized the cockpit and interior. The SPX added stronger engines, winglets, digital engine control, and enough extra range to earn its later life as the Gulfstream G100. Same family, three clear steps forward.

Pick the one that fits your mission and your budget, get a solid inspection, and you have a fast, characterful midsize jet with a genuine story behind it. Even among the rarest fighters and the rarest jets in the sky, few aircraft show off a decade of steady improvement as neatly as the Astra line does.

Whichever Astra catches your eye, let Flying411 help you compare the variants, check the market, and find the airplane that is right for you.

Frequently Asked Questions

What is the biggest difference between the Astra SP and the Astra SPX?

The SPX has stronger engines, winglets, digital engine control, and Pro Line 4 avionics, while the SP has neither the winglets nor the extra power. In short, the SPX is the higher-performing airplane, and the winglets are the easiest way to spot it.

Is the Astra SPX the same as the Gulfstream G100?

Yes, essentially. After Gulfstream acquired the type certificate, the SPX was rebranded as the Gulfstream G100 in the early 2000s, with the airframe staying the same and the name and support network changing.

How many Astra SP jets were built?

Records commonly point to around 37 Astra SP airframes before the SPX replaced it in production, which makes the SP the rarest of the three main Astra variants.

Do all Astra models have winglets?

No. The original 1125 and the SP have clean wingtips with no winglets, and only the SPX (and its G100 identity) added them, which is why winglets are such a reliable way to tell the versions apart.

Is the Astra a good midsize business jet to buy used?

It can be, especially the SPX, thanks to its range, speed, and better parts support, but the smaller support network and older systems mean a careful pre-purchase inspection is essential before buying any Astra.