Are you talking about wanting to mod the game for higher fleet caps, or you're just learning the game and can't find the research to increase fleet supply beyond your starting 100?

I'll assume the latter. There's a special tab of the research tree, should be the fifth one down, right below your diplomacy tree (name varies based on the race). There you can research techs to expand your fleet supply for ships or command points for capitalships and titans.

 No, I am looking for Directed Reproduction and Captive Suppliers. How do I find them on the tech tree? I've looked at everything, and I can't find them.

I am currently playing as Vasari Rebels, if that helps.

Do what Goa said, it's on the research menu, below Warfare, Fortification, Empire and Manipulation there should be something called Fleet Logistics. From here you can increase your supply (bottom), which will increase your supply but also increase your upkeep, and cannot be undone, so make sure you're ready to do it. The top one increases your command, allowing you to build more capital ships / a titan. It has no effect on upkeep, but has a high one-off cost.

There's also Phasic Transmissions on tier 6 of the Empire tree. This will increase your supply by 8% at stage 1, at the cost of 1400 credits, 250 metal and 400 crystal, and 15% at stage 2, at the cost of 1500 credits, 275 metal and 425 crystal. This will have no effect on your upkeep, so it's great for the late game where you don't want to have more upkeep but need / want more fleet. This is ony avalible for the Vasari, and so gives them an advantage in the medium to late game. It's probably one of their best techs.

Finally, there's the Supply Pact, which is the final pact for the TEC. Diplomacy isn't a big part of Sins, so it rarely gets used, but if you have a TEC teammate willing to do it, the supply pact will give both participants +100 supply and -15% upkeep, which is huge in the late game when upkeep levels can reach over 80% - the Supply Pact can almost double your income, as well as letting you build more stuff.

And that's it. Primarily you will be using the Fleet Logistics research, as it's the easiest to get. Don't upgrade it too much or too early though, as you will find your income rate is decreased and you can't afford to use the supply you got - it's worryingly easy to do.

If you open the research windows there is an category for all of those researchs. It is located above the Artifacts tab. Just hit the top first for more capital ships crew and the bottom first for more fleet supply. The research you mentioned is locatd there. It just might not be the first level so just mouse over the other symbols.

This is what I have been trying to do, but it tells me I need one point in [blah blah] and one point in [blah blah]. I am trying to ask how I can get these on the tech tree.

Build research stations. Either one will do. Then click one.

http://www.youtube.com/watch?v=NRI_nxmpGWU&t=8m0s

At 8:04 I open the fleet logistics window and start research on the first fleet supply upgrade. As you can see it's the one on the bottom of the fleet logistics tab (may have a different name for Vasari but its in the same location). As Ryat mentioned you need at least one research lab.

 I am not sure if it's me who is misunderstanding, or everyone else. Sorry about this, guys, but I can't find what you are directing me to. I am talking about Rebellion. I have been playing this game since it was Vanilla, and things have changed with the new version.

In order to increase pop-cap, I need 1 point in Directed Reproduction and 1 point in Captive Suppliers. I have a crew available for Titans/Capital Ships, but the game is refusing to let me use them. Clicking on the research labs does nothing.

I have no idea what is going on.

Sorry, guys, just disregard this entire thread. I've worked it out.

I've been working too hard recently, and my mind's all over the place. 

Thanks for the help, anyway.

Hi, I have the same problem, how did you solve it? I have researched everything, but nothing helps

I know im missing something or doing it wrong, just cant figure out what it is :-/

Videos are your friend.