The design is for a birthday invitation, but it's a great idea for a launch party invitation! Encourage your guests to bring their balloons. They can double as a party game if you put little messages inside of them!
DIY Birthday Party Banner in a Box Tutorial from Oh Happy Day here. Lots of punches are listed for this tutorial but you don’t really need them. Sticker paper however is cheap and will make this really easy. You could also sandwich the banner between.