I have fairly advanced COPD and use an oxygen concentrator while sleeping. I was hospitalized twice in 2016 due to respiratory infections. Actually, I believe the second hospitalization was due to not resolving the first one appropriately. This spring and summer, I have worked myself to long walks of up to 4 miles in mostly flat terrain during mild weatherr. I really feel the strain when I do encounter hills. This past weekend I noticed a worsening cough and shortness of breath. I am set to make an eight hour flight on Saturday, so I asked my doctor to prescribe me a Z pack which he did. My last dose is to be taken tomorrow. I am now reading upper 80s and low 90s at rest. I already have a Simply Go concentrator for the trip prescribed as a pulse level 3 while flying. I have been looking forward to this vacation for so long, but I am, needless to say, about anxious about the flight.