It is a question more about culture than German language.
I live in Poland. Last week I found in my garden a balloon out of the gas.
On the balloon there was a drawing of a girl saying
Viel Spaß mit Carina
There was a Sheet of paper with a wish fixed to it that says:
Wir wünschen Euch einen gut funktionierenden Wecker, damit Ihr immer pünktlich zur Schule kommt.
Of course I can translate the saying on the sheet as a wish for a schoolchild for better functioning of his/her alarm clock that he/she can be at school on time.
I find myself this situation very funny and I wonder what cultural event It could be. Maybe Birthday? If the child was Christian, maybe Eucharist/Confirmation. If she was married at the age of 19 maybe it could be her wedding?
Do someone know this kind of tradition in Germany or Austria to leave flying balloons with wishes printed and fixed to them? I am very curious of it.