My MacGuyver method for repairing the airline did not hold out very long, so I needed something structurally. Fortunately, Mercedes sells a piece of airline (1.5m) for repairing/maintaining the Airmatic system, which was exactly what I needed.

Partnr: 2203271045 / A2203271045
Costs: about 20 euro

MacGuyver vs new airline. I used some teflon tape for extra safety
I found some hose which fitted around the airline perfectly (also for extra safety against rubbing)