I just took a 11 hour flight yesterday. My GP said I was find to fly beforehand without oxygen.
However, at certain brief times during the flight my oxygen level dropped to 92/93 and would get mildly SOB and would start PLB. This would last for 5 minutes at a time and probably happened 3 times. Oxygen never dropped below 90. The rest of the flight my sats around 98 and had no issues.
Anyone have any ideas why it would happen briefly on the flight and was fine for the majority of it? My sats never go below 95 on land, even when exercising.