Large volumes of a gas can be put into a small cylinder and transported easily. The reason behind this is:
Gas does not have definite shape and have high compressibility
Large volumes of a gas can be put into a small cylinder and transported easily because gas particles are loosely bound and have a lot of free space between the particles. So it is easy to bring the particles closer together by applying some pressure which reduces the volume they occupy. This lets us put them into small cylinders.