I use O2 for flying and at altitudes over 3000. Before you go off to high altitude, I'd suggest you check with your doc to see what s/he thinks. There is a test you can ask for called the High Altitude Simulation Test. That will tell you whether you will need O2 at altitude and how much.

Jean

Thanks so much for the info. Jean, I will ask my doctor about the high altitude simulation test.

No oxygen use

I fly all the time and have not had an issue. Trip to Europe two weeks ago and no issues. Going to altitude this weekend, we'll see how it goes.

Trip to Grand Canyon @ 7000 feet went well. No breathing issues 😀