[Jellyfish]

Basically, making FRED accept ships from two different mods. How do I do that?
I tried putting all the related .VPs in the same folder, but FRED ended up accepting ships from only one of the mods and ignored the ones from the other. Merging the .VPs with VPMage yields the same result.

[Jeff Vader]

Maybe try extracting the ships (and related stuff) you want to use from the .vps, find the necessary table entries, compile all the stuff into your mod folder and yeah. If you just punch a bunch of .vp files into the same folder, they may contain many ships.tbl files which will then battle for supremacy. And sort of like with Highlander, there can be only one (ships.tbl used by the game engine at a given time).

[Jellyfish]

So all I need to do is to somehow fuse the ships.tbl together? Or do I need to fuse all duplicate tables?

[headdie]

if the file extension is .tbl then the game will only read one at a time, so any cases where you have more than 1 only 1 will be used.

http://www.hard-light.net/wiki/index.php/Ships_and_General_Mod_Creation this might help you out.  Also looking up table files on the wiki will help you greatly

[Droid803]

The way you "combine" two mods is to create your own mod with the components of both.
There is no easier way.

basically means copying together entires into a single ships.tbl (or -shp.tbm), as well as associated weapons, etc. into their respective locations and resolving any conflicts.

[Rodo]

Like everyone said, it's easier to just grab the two ships and include them in your own mod.
This is valid if you are planning on using these two ships quite often in your missions or if you are planning on making a campaign or something like that, in that case your will need to make your own mod eventually.

If you are just making a single mission, then you could also make a mod folder and use the mod.ini file and include in there the two other mods that have your ships, then just use the launcher to select your newly created mod with the mod.ini and the ships will be loaded (be advised that some weird stuff might happen from merging two different mods just like that).