I have had mild long covid for nine months now, and I've taken a couple plane trips during that time. The longest flight was four hours. Both of them went fine. The main issue for me was the walking in the airport. I looked up how far I would have to walk and made sure I always took the escalators (I always used to take the stairs!) and the people movers. The plane ride itself didn't have any effect on my shortness of breath or other symptoms. (I also went from sea level to high altitude, and that also didn't bother me any more than normal.) But maybe check with your doctor? Especially if you've seen a pulmonologist, they might be able to talk to you about the changes in pressure and altitude and how that might affect your lungs or blood pressure.