You can't take any O2 EXCEPT a POC on board a plane. Take a look through the archives; there are lots of discussions on this topic. You can certainly do it, but you need to know the rules and what your carrier requires. That requires research, and you can do that here by looking at old discussions.

Yes,some airlines also supply oxygen onboard,but not free,
I have the inogen oxygen machine very potable which I will be travelling with to Burkina Faso next year. Good luck and wishing you all the strength.

I believe that the problem you will have is being on 02 24/7 when you arrive in Nigeria. I lived in Kenya East Africa and I would have had to purchase a concentrator there and power is very unreliable in Kenya. I would have been tied to my home. So I moved back to the states where I have now been on 02 since 2014 and can no longer fly as the cost to rent a portable unit costs more that my plane fare!

Yes you have to get prior permission from the airline and usually they prefer a concentrator in lieu of portable tanks

And also higher 02 level is needed when flying due to altitude changes. I'm on 3 litres per minute so I move to 4 when flying. Also you need a letter to show at security from your doctor plus the airline has thrown from.and I always get the disability assistance free of charge which the airline provides. I get the wheelchair as I have trouble walking the airports. It is a wonderful service and you can also get your seat selection free of charge. Hope this info helps anyone planning to fly.