Balloons do not fly by themselves, but only if they are filled with helium or grisolar and if the balloon itself is not too heavy for the amount of helium it contains. That is why small balloons do not fly, but only larger dimensions and sufficiently thin walls, so balloons made of aluminum foil or PVC are used most often for helium filling. These materials, in addition to being lighter, are not as porous as latex, so they release gas much more slowly and can fly for weeks. The latex balloon must first be filled inside with a special expencive impregnation gel to fly for several days instead of just a few hours. Modelling balloons from which the sculptures are modeled do not fly because they are simply too heavy. The production of foil and plastic balloons is cheaper and it is easier to realize various shapes and finished flying figures.
The problem of releasing helium balloons is because they do not fly forever and sooner or later they will burst or blow out and fall to the ground and become just a piece of non-degradable trash.
Why do people even release balloons? Sometimes children just like to watch the balloon go, but much more often it is an organized event of an association or club that promotes an idea by blowing up a balloon. Then tens of thousands of balloons are suddenly released into the air, and it is often latex balloons that are most attracted to animals, especially if they fall into the water because they look like fruits. Animals eat them, and the balloon can suffocatethem or block the flow in the stomach and then animals dies in agony. There has also been an increasing number of strangulation animals by tapes which tied on balloons.
There is a growing movement in the world of the "Balloons Blow - Don't Let Them Go" movement that promotes the fun of ecological substitutes for helium balloons. Non-flying balloon decorations can be a lot more fun than watching a balloon go, because you can injoy in them much longer.
But how big is the popularity of helium balloons? Helium is natural gas and cannot be produced, and once released into the atmosphere, it is lost forever. Most of the helium used worldwide is extracted from Earth's crust on US soil, but these underground reserves are not unlimited. In the 1920s, the US began storing extracted helium in underground reservoirs in order to have reserves in case of gas shortages, which is important in industry, various scientific studies, used in some machines, and is essential in medicine and helps rescue newborns because it is used in cooling superconducting magnets in MRI scanners in hospitals. No substitute for helium for many purposes has yet been found.
But in 1996, the US sold its stock, and at that time the price of helium dropped and its popularity at parties increased, and today is such a situation that it has become a major environmental problem.
Now prices are rising again because the world's helium supplies could be gone in our generation and there are more and more campaigns in the world against the waste of helium for decorations.