Supplemental oxygen during air travel should be used if your arterial blood oxygen (ABG) levels are low or borderline-low at sea level. A level of 94% would be fine at 5,000 feet but might be borderline at sea level. You should check with your lung doctor on this and, it will probably be necessary to check arterial blood gases for a recommendation to be made.
Some large hospitals have high altitude chambers in which your oxygen level (oximetry) could be checked at the simulation of 8,000 feet (the average of commercial air travel).
Good luck