@xanvankay, there are a couple of discussions in the group about flying with a brain tumor or after brain tumor surgery. You may wish to read the guidance and experience of other brain tumor patients in these related discussions with members like @pejiota4jack @teresaallen
- Time for surgery: Questions about travelling home after brain surgery https://connect.mayoclinic.org/discussion/time-for-surgery/
- Is it safe to fly with a brain tumor? https://connect.mayoclinic.org/discussion/is-it-safe-to-fly-with-a-brain-tumor/

But your question is specifically about travelling to and spending time in a place that is at much higher altitudes than you are accustomed to. Am I right?