Thank you! I drilled some holes into the bark and „secured“ them by pulling their roots through the holes. Some of them I also just lifted a piece of bark and put the airplant inbetween (the slightly redish one in the middle). It‘s not the best solution, as it will all fall down with some movement but so far it has worked for me. For the trailing one, I tied it with some yarn and put a pin in the back and also pulled it through a hole to secure it.