When you first purchase a simulator, you get the "world" (consisting of landscapes, water, and cities), the weather, airports, and aircraft. However, not all simulators are created equally. In X-Plane or Infinite Flight, what you get is very flyable right away. For Prepar3D, enhancements to the default weather, camera views, and aircraft offer a significant improvement over what’s available by default. And users of the newly-released MSFS will find that, while the “world” and stunning visuals offer a great VFR experience, you won’t find the same ability to fly detailed, realistic airlines in the IFR world just yet.

Add-ons, available as both “freeware” (no charge) or “payware” (for a price), are modifications for your simulator. In almost all cases, they’re offered by third parties. Some, like Orbx or Navigraph, are relatively large companies with strong relationships to the simulator and real-world aviation. Others are smaller companies or even just passionate simmers who have found a need to help fill. Add-ons can be just about anything—some examples include:

Airplanes

• Modifications of an aircraft to give it more realistic properties
• An entirely new aircraft
• A repaint or livery for an aircraft
• A component of an aircraft, like a GPS or FMS

Scenery

• An update to an airport that fixes bugs (like missing taxiway signs and runways) but leaves textures unchanged
• A complete overhaul of an airport that makes it look completely different from the default airport
• A modification to a distinct area like a city or landscape
• A large-scale modification to a wide area or set of objects

Utilities

• A pushback feature
• A program that provides weather depiction in your simulator
• Better camera angles and recording options

Many times, developers who charge for their "payware" software have put in the extra time and effort to make the product worth the money. But that’s not always the case, and there is some incredible "freeware" available too.

So, where do you find all these add-ons?

Many payware developers have websites where you can find and purchase their products. There are also marketplaces like Aerosoft and SimMarket that have add-ons from several publishers. For freeware, the AVSIM library, FlightSim.com library, and X-Plane.org are good places to start.

Choosing the Right Add-ons

To help select what products might be right or will get you the best value, we’ve listed some considerations below to help guide you in evaluating potential products or add-on developers.

Think about what simulators you use.

Generally, it’s difficult to find high-quality add-on products that are compatible with more than one simulator (though it’s not unheard-of). If you fly multiple simulators, you'll likely find that different simulators are best suited for different types of flying. For example, you might choose to find a general aviation aircraft for X-Plane but a jetliner aircraft for Prepar3D.

Evaluate freeware options first.

In general, you’ll find higher quality add-on aircraft and scenery when you pay for it. However, that’s not always the case. One of the most popular aircraft in X-Plane (the Zibo Mod 737-800X) is entirely freeware! The nice thing about freeware is you can download and install it for no cost. So, if you find a freeware option, consider installing it and trying it before you buy the payware option.

You can find freeware on sites like AVSIM and X-Plane.org. For payware products, marketplaces like the ones we’ve listed in our Flight Simulation Resources Guide, or just Google, are good options. For example, let’s say you’re looking for an add-on Boeing 757 for X-Plane. Searching “Boeing 757 addon xplane” on Google leads you to the FlightFactor Boeing 757, a highly-regarded Boeing 757 add-on.

Leverage the community for help

If you’ve found a few payware options and are looking to compare them, look for reviews on a reputable flight simulation news website or search YouTube for reviews. You can also look at the developer’s website or see how active they are in the community. Developers who participate in events like FlightSimExpo, Flight Sim Cosford, and the Oz Flight Sim Expo tend to be more active in the community.

In general, the best flight simulation developers will be:

• Well-established, having produced one or more add-ons
• Selling products through multiple stores, likely including their own
• Mentioned regularly on news websites like FSElite and Threshold
• Sponsors or exhibitors at large community events

Remember, the fact that something is “payware” or listed on a popular downloads website does not necessarily mean it's right for you. Picking aircraft from well-known, popular brands is a good place to start, but always conduct your own research before buying.

Most Popular Software Add-ons

In 2020, news and reviews website FSElite polled the community to find out the top add-ons. Out of over 10,000 votes, these were the top payware add-ons selected by simmers from around the world, ordered from least to most popular.

In addition to showing the community survey results, we wanted to share what some individual simmers had to say. Here’s the personal "top 5 add-ons for Prepar3D" from Mike ("Moosestaffa" on Twitch and "The Flying Moose" on YouTube):

And the best parts about X-Plane, in the words of Ty, known as "catstrator" on Twitch and YouTube:

To give you a sense of what’s available, we’ve categorized FSA Software Partners by the types of add-ons they produce. Software Partners are added to this list when they offer a discount to FSA Members.

However, this is just a fraction of the payware developers out there—and don't forget about the freeware community too! Part of the fun of flight simulation is looking through what's available to find the right add-on for you.