The Effects of Commercial Air Travel on Patients Suffering From Pulmonary Hypertension

The aim of this study is to 1) descriptively report possible in flight events and 2) to provide regression analysis if the number of events are statistically significant in their prevalence and thus are useful in finding possible parameters in echocardiography, right heart catheterization, laboratory findings, spiroergometry as well as six minute walk test to produce a risk assessment for possible expected in flight adverse events as well as a recommendation concerning the need of supplemental oxygen for each individual patient. The investigators therefore want to find out: 1. In which subgroup (if applicable) of PH patients in flight adverse events are more frequent. 2. Whether there are parameters (from blood samples, blood gas analysis, World Health Organization-Functional Class (WHO-FC), Six Minute Walk (SMW), echocardiography, right heart catheter (RHC)) that are able to predict in flight need for additional oxygen and/or possible adverse events.