How to inflate a balloon in flight

Hydrogen balloon and helium balloon, hydrogen balloon is not desirable, it is too easy to explode. Helium balloon is very stable, so it won't explode. Very safe. Inflating can only be done by yourself. There are three steps: buy a balloon, buy a helium tank and inflate it. You should buy a color balloon, purple and white, and buy it online. Helium tanks are also bought online. A 22-liter tank is less than 150, and can be filled with 40 balloons. It is not enough to fill 120 balloons with three tanks in a space of more than ten square meters. The helium balloon can last for 3-4 hours after it is filled, so the time should be accurate. There is also air-proof glue on the internet. I used it half a month ago. It's too much trouble. It's like squeezing glue into a balloon by hand, so I have to pinch it. Not recommended. If you want to hang something under the balloon, the lighter the better. I have a practice class.