Actually dragging (or wheeling in) a wire or having a wire car supplying the plane with electricity during takeoff would work too.

After doing more of the math, I realized that the energetic cost of takeoff is quite a small fraction of the overall cost. So the only real benefit of the catapult would be to reduce the size and weight of the propulsive machinery on the plane. So externally providing just the electricity wouldn't be much of a benefit.

I didn't say which type of catapult. I don't need ICE showing up at my door.

My cats would always go in the litter box no matter how horrifying I let it get. It was actually pretty impressive.

I used to drive a '76 Rabbit that got 40 mpg (and with a carburetor no less). Unfortunately, it had no chance of passing an emissions inspection and not much chance of surviving even a low-speed collision.

You can rethink the engineering with electric motors.

One of the other limitations is that you're stuck with propellers if you're using electric motors, so your top speed is going to be significantly slower than jets. Unless you do the Tu-95 thing with contra-rotating props whose tips exceed the speed of sound, and then you have monstrous noise problems.

Hell yes, TIM was my second-favorite game of all time. Lemmings is really the best, though.

the priest/ monk class in the middle-ages

Lol as if those motherfuckers were celibate.

Hideous. Look at those fucking loose cables.

This seemed intuitively wrong to me (like, way too low a cost), but: 25,000 pounds moving 100 mph is equal to 11,331,007 J of kinetic energy. Since 3.6 million J equals 1 kWh and 1 kWh on average costs $0.17, that means you could accelerate 25,000 pounds to reasonable bare minimum flying speed for about fifty cents (not considering efficiency of the machinery). My mind still can't process this, but math is math.

On the other hand, looking at it from a potential energy perspective it's a bit more expensive. 25,000 pounds at a cruising altitude of 10,000 ft. (still quite low from an airliner perspective) is about 339 million J, 94 kWh or about $16 -- the cost of lunch at MacDonald's.

Since a plane requires the most thrust at takeoff, you could use ground-based catapults to get the plane to takeoff speed (or faster even) and then you could carry smaller batteries and propelling machinery. For extra fun, you could have landing planes snag a wire and use their momentum to accelerate a plane taking off.

To save even more weight, since you're going airport-to-airport you could leave off the landing gear and just have the planes come down on a bouncy trampoline-like surface. If you think that's batshit crazy, the British actually experimented with this idea for their aircraft carriers in the 1950s.

Edit: to make these numbers more realistic I'm going to assume something like a 737, which can weigh something like 150,000 pounds fully loaded (this includes fuel but you'd need batteries instead for an electric plane). Getting this to a 150 mph takeoff speed would take about 100 million J (getting it then to a cruising speed of 500 mph would be another 233 million J, but that's pretty minor compared to the other costs). Climbing this plane to 30,000 ft would take 6.1 billion J. Resisting a drag force of 5000 pounds (about what a 737 experiences at cruising speed at 30,000 ft) for 500 miles (the distance from Cleveland to New York City) would need 17.6 billion J. Assuming landing is free (fuck TANSTAAFL) that means a typical trip needs 23.8 billion J or 6618 kWh or $1125. Assuming a real-world efficiency of 25% means the actual cost would be $4500 (which is in the ballpark of what jet fuel costs). Assuming 200 passengers, that's $22.50 per person. Not exactly "$5 of electricity" but surprisingly small.

Feel free to check my math, my brain hurts.

Try Lemmings while there's still hardware around that can run it.

I used to grow vegetables in a garden until the groundhogs showed up. I bought a "humane" box trap, but every time I caught one it would rip out its own claws trying to escape before I could dump the literally bloody critter a few towns over. I have no idea if their claws grow back, probably not. The whole routine was just too depressing so I gave the trap away and had the garden dismantled and plowed under. Now I buy vegetables at the local farmer's market.

I have no clue if it actually is dangerous to go USA or it just seem that way.

USian here. It's not dangerous as long as you're not even vaguely latino.