LOL, EMALS on carriers requires 60 Mw of power to function, they gonna be carrying a mini nuclear reactor to power that?
Also whats even the point since those UCAVs need airfield to land anyway.
the launch support would only last for about 2 seconds, so the required energy is about 30 kWh with your number. This seems doable when your typical EV have about 100 kWh and can deliver 1MW (e.g. some BYD models). For extra umph, you can add some capacitor banks and parallel connect 10 EV batteries, and still be within 1-2 m3 volume.
I also think your power requirement at 60MW is for +30-ton fully armed fighters, while a usable drone can be 1 to 10 tons. So, power will most likely be a lot less. For reference, a 10 x standard EV batteries can deliver +10 MW continuously and a lot more in bursts. So, even 60MW bursts are not outside the reasonable domain for a custom-designed blade battery pack (the same style that you use to jump-start your car).
The obvious use case for this would be additional payload for a normal drone delivered close to the target. The drone can always land in an airfield far away. However, I'm still not sure about the concept as it looks very funky but not undoable from physics point-of-view. For example, you would need additional hardware to get the drone up that ramp.
Something that launches a large drone from one launcher, would be more interesting. There probably even exist, but I have only seen smaller drones launched this way.
As a side note, I think development is ongoing to use similar technologies to launch rockets/missiles instead of cold lunch with compressed gas.