Perhaps, you didn’t realize it but most nations have signed a treaty to prohibit gas-air weapons on the battlefield. Yes, that’s a fantastic way to describe it, and you certainly would not want to be on the losing end of this game. Incidentally the United States didn’t sign the treaty.
Why you ask, well, we are the inventors of Napalm, and the more modern versions of gas-air weapons, that are even more deadly than ever before, also more accurate, truly scary stuff, and if the 1000-degree and fire will not kill you, all the oxygen is pumped to the fire so that you suffocate, either way you have no escape. Even nations refusing to sign the chemical weapons ban sign were worried about gas-air weapons in the skies.
Nowadays, we could easily send those deadly munitions by UAV (unmanned aerial vehicle) or drone. Again, scary stuff, but allow me to tell you of an even scarier potential invention for robotically dropped gas-air weapons using swarms of UAVs constantly refueling the weapon pods using aerial refueling and unleashing this hell for hours and hours until there are no enemy infantry everywhere.
First, I suggest having a pod of polymer balls which expand when filled to 2,000 times their original size. They will be filled with a liquid fuel-explosive mix, and the polymer balls un-expanded will sit inside the pod and after the fuel enters the room”x-amount” of balls will be discharged and like a membrane sponge soak up the gas until the inside cavity of the pod is stuffed. The liquid-fuel explosive will be transferred into a reservoir at the UAV, the UAV will then search and strike accordingly within a swarm of 100s of different UAVs.
Once depleted of polymer balls and gas that the UAV will fly back up into the appropriate elevation and meet up with the aerial re-fueler and repeat as long as necessary, perhaps days? Yes, I do have drawings, sketches and schematics and in case you’ve got a security clearance, then come look me up. No one wants or enjoys warfare, but if you find yourself in one, you must win, and decisively. Such a weapon is guaranteed to break the will and moral of any infantry of any enemy. Please think about all this and think on it.