Why did FSX add-on aircraft file sizes jump from ~19 MB to GBs after the new version?

What you’re seeing usually isn’t FSX “suddenly getting bigger” so much as the way newer developers package aircraft now compared to the older FSX-era stuff that really could come in around 10–30 MB.

Why add-on aircraft are now measured in GB

1. Higher-res textures – A lot of modern repaints use 2048/4096 textures (sometimes multiple texture sets: exterior, VC, cabin). That alone can push an airplane into the hundreds of MB or more.
2. More model/detail content – Higher polygon models, more animations, more interior modeling, cabin modeling, etc.
3. Sound sets – Many packages include large “HD” sound recordings and multiple variations.
4. Multiple variants bundled – Instead of “one model,” a single installer may include several engine types, passenger/freighter, winglets/no winglets, multiple liveries, etc.
5. Bundled extras – Some aircraft installs include documentation, paint kits, configuration tools, effects, and sometimes even optional features all in one package.

First thing to check: are you actually downloading FSX aircraft?
One common gotcha: people grab a package meant for a newer sim (or a “HD” version / multi-sim installer) and it includes a lot more content than the classic FSX-native releases did.

Practical things you can do

1. Look for an FSX-native / “lite” version of the aircraft (some developers offer a lower-res texture option, or separate downloads per variant).
2. Install only what you need – If the installer allows choosing liveries/variants, don’t install everything.
3. Downsize textures – If you’re comfortable with it, converting 4096 textures to 2048 (or 1024) can save a lot of space. (This depends on the aircraft and how it’s packaged.)
4. Be careful deleting – Randomly deleting folders inside a payware aircraft can break gauges/sounds/models. If you want to reduce size, do it methodically (usually liveries are the safest “optional” chunk, if they’re separate texture folders).

A couple quick questions so I can steer you the right way

• Which exact “new version” are you referring to (FSX Steam Edition vs boxed FSX, or something else)?
• Can you name one or two aircraft you downloaded that are showing up as “GBs” (and where you got them)?
• Are you seeing the size of the download installer, or the size of the installed aircraft folder under SimObjects\Airplanes?