HAST- High altitude simulation test. Surprising that pulmonologists often do not know about this test although those who handle PH do. In NYC surprising that only Bellevue Hosp can offer it.
I cannot send you the link through your website, but the name of the 2011 study is "Health Effects of Aircraft Cabin Pressure in Older and Vulnerable Passengers". If you Google it you will find it.
On my Linkedin page at the time I posted that "FAA regulations do not require air carriers or passengers to provide reports regarding medical events on board aircraft or individual health data. The FAA has no database with such information, to inform medical researchers about the effects of flying, particularly to older passengers and with pre-existing conditions that could be affected by insufficient cabin pressurization relative to their need. This is also true for foreign airlines."
If there is no data created or maintained it is hard to study the medical issue and to know the degree of the problem, particularly if passengers have no symptoms during the flight and may not think to check their oximeter during the flight, if they have one.