You can only fly with a Portable Oxygen Concentrator. None of the POCs available at this time can produce more than 3 lpm continuous. If you can manage pulse dose, you might be able to get along with something like an Inogen One G2 which does produce a big enough bolus at its highest setting if you breathe slowly enough, that you might be able to manage. If you can't do pulse, you're out of luck. I'd check with your doc and perhaps ask for the High Altitude Simulation Test. You could try it with both a continuous and pulse machine. Just be sure you're using the machine you'll use on the plane. POC's are all different and there are no standards for setting or size of the bolus..

Courtesy info via a friend:
G3 portable oxygen concentrator with an extra battery to allow for international flights, which should give me 2 lots of 8 hours. I will then need to do a 4 hour stopover to recharge the battery if needed.

@22% Retainer/Gas Exchange Issue, i have done a Long Haul Flight of 12 hours with no oxygen in 2013...All my Safe to Fly Certificate was a PFT test and 6 min walk, which registered 95% during and after.......BUT not sure i would risk it again LOL

http://oxygensolutions.com.au/

I don't fly anymore
They do make portable concentrators that put out a higher 02 levels
Ask your 02 provider if they have any
If not maybe they can recommend a company that does
Check with your insurance company
Slow and steady we go