This page in our guide to Rage 2 focuses on how to find the MBTV balloons. You will also learn how to pop the balloons and how to get to the chests that were attached to them. Pop 17 balloons to unlock Can't Stop Pop silver trophy.
You can find balloons during exploration. A balloon icon can also appear on the world map (example in the picture). It is worth noting that this is not a stationary icon - each balloon is in motion.
Reach one of the balloon markers on the map - drive a vehicle if the balloon is farther away. Find a balloon in the sky. You can pop a balloon with Ranger Assault Rifle or any weapon that works at a longer distance.
Each balloon carries a chest that will fall to the ground. It will appear on the radar at the top of the screen. You can get to the dropped cargo. Shoot the chest to make it explode. This will allow you to collect loot that has been transported by the balloon you popped.
Watch out - a mutant can jump out of one of these chests. If this happens, jump backward and only then attack the enemy or use some offensive ability.