is there a way to auto deploy more drones, use case is if there are no free drones. maybe depot is more "hangar" or you can place a drone into a refueler?

No, they have to be placed manually

I think it's theoretically possible to auto-deploy when a depot(s) has 0 drone count and then use a mod like Recursive Blueprints+ to place more drones. But I haven't tried that mod, and some circuitry knowledge is then required

I could consider adding something that would make it easier, or something that will just auto-deploy new drones during high demand. But I'd have to check performance first, swarms can quickly eat tick speed when they're all working. But I don't have the time currently, so it might take a while

I might take a look at recursive at some point, it was a suggestion/question not a demand

I absolutely did not see it as a demand, I did get excited about the idea though. It's something I hadn't considered, but makes sense to have in retrospect

Another mod that might be easier to use is AAI Programmable Vehicles as I believe it has a structure that can auto-deploy vehicles on a circuit signal. It might work since the Cargo drones are considered cars, and it'll probably look wonky. But again, haven't tried

Alright. If you're still interested I've had a proper look at this now. And even have a working implementation, but graphics and GUI is still missing if you want to give input or thoughts before I complete the first draft

So bad news first; due to technical limitations I couldn't come up with a good design for a hangar structure which drones can enter (Like how bots work), at least no design I'm happy with that wasn't too complex or had a bunch of edge-cases. So putting that on the back burner for now

However, I have made a new Deployer structure that can auto-deploy new drones. It works by inserting a drone item into it followed by fuel. Once fully fuelled the drone will be released
- By default drones will only be released if there are no drones without a task (So the amount of available drones are 0). This can be disabled in the deployer so it always deploys
- There is a limit on how many drones are allowed to be deployed, deployers stop once the amount of drones on that surface reaches the cap. This limit is set in the deployer or using circuits
- Deployers can also output the current amount of drones and how many of them are available. Again, this is configurable in the deployer