How is that even supposed to stop suicide bombing when the only planes that do care about flying over your own site are those that already pull up as kamikaze pilots will stop existing befor that?
The big problems I see with this are
A) Balloon can only intercept planes after they passed the cap. (and with it tossed their bombs) but a kamikaze wouldnt even have reached them as he already crashed near the objective.
B) Useless if enemy has rockets so it doesnt even have to come that close
C) Construction of those balloon is just stupid
D) the only way they can stop an enemy pilot is when they are built on the enemy side of the map but how many times do you even get there and why not just cap?
E) Enemies will be able to shoot them down befor they crash so they are made useless
F) Friendly planes will be affected way worse by them as they count as friendly structures and they wont be able to shoot them paired by the fact that the balloons will be most commonly placed on your own side AKA your own pilots corridor toward the cap.
G) Enemies can built it to 95% and wait until you are directly ontop of them to finish the last 5%.
The moment it would pop into existance it would already be to late for the pilot to react and it is by not means the pilots fault. This would be a very cheap tactic that would be toxic af and immersion breaking the moment it happens because that 20m by 10mm balloon doesnt just come out of thin air IRL.
H) Seeing balloons pop up in the pacific or tunisia etc. would be very doubious at best and irritating for everyone else.