As well as what the other commenter says, a balloon cost a lot less than the jet fuel to scramble a jet and get it to where the balloon is, and then the jet can't be somewhere else. The goal isn't to make an undefeatable weapon, it's to cost the enemy enough money that they've got no choice but to give up on the war and go home.

Sure. That assumes that this is detected and that the Russians happen to have a fueled up Mig 29 with crew available and time to prep the aircraft and intercept. That requires like a few dozen properly trained people to have actually showed up to work moderately sober that day.

ofc it should if you know where it is. balloon and ropes are plastic and therefore non-reflective for microwaves. drone is also largerly plastic so the only metal bits are wiring, battery and warhead

but wait, it gets worse: you can shoot down balloon, but after release drone is still pretty high up but it's now fast, and has just as small radar return as before

shouldn't a few rounds from a mig 29 be able to bring a balloon down without any effort? Sounds like a skill issue.

So firstly at 5-7km you shoot a balloon it doesn't just deflate and drop. It'll keep floating (slowly returning to earth over days).

You've been vectored in by ground controllers. You have to spend a heap of time waiting for orders and directions. You can't even see it properly. Its mylar. The FLIR, if its working, isn't showing shit when it comes to mylar.

Secondly imagine you're doing 800kph in a mig-29. Your radar won't lock onto the balloon.

So you somehow line up and setup guns for the shot. Bam, your past it before you have time to even think.

So you line up for another pass. You slow your MIG down to 350kph. This time you have maybe 5-8 seconds before you're pass the target.

You have no idea if you've hit it. You've probably missed it.

A couple more passes and now you're running out of fuel and or ammo (tactical fighters usually have enough ammo for a 1-3 second total firing time) and have to return to base.

Plus all the running cost stuff the other posters have pointed out makes using tactical fighters to shoot down balloons a completely losing proposition.

When the Americans shot down those Chinese balloons it was a near miracle they were able to do it.

Of interesting to note is one of the core applications for the Soviet / Russian A-60 airborne was to shoot down American "weather" balloons.

Really fascinating video (that goes into trainspotting levels of detail) by Not a Pound for Air to Ground

https://youtu.be/tO2Jk5jjzdE

What other comments seem to be missing (lol) is that Russians are afraid to pull up any aircraft that close to the front and that high, since patriot AA traps set up by Ukrainians a year or two ago.

Do not underestimate how hard it is to shoot down a lighter-than-air aircraft with projectiles is.

The holes matter but nowhere near as much as you think.

I guarantee I could bring one of these down with a pencil. The issues are knowing where it is, and getting the pencil to it...

shouldn’t a few rounds from a mig 29 be able to bring a balloon down without any effort?

Nope. The U.S. did this to the U.S.S.R. constantly during the Cold War and the Soviets had less than a 5% success rate shooting down the balloons.

The US struggled with the one from China three years back. In the end it took an F-22 and a very expensive missile to get the job done.