Firstly NOS is Nitrous-Oxide, which is never used for paintball. "nitrogen" is another term for High Pressure Air tanks, because air is primarily Nitrogen. you must buy a HPA tank to use HPA. Not only can you not physically fill the wrong tank with the wrong gas, but It would destroy your burst disk if you tried.
You can not bring Co2 tanks on a air plane. As it could be used as a explosive, so it would be confiscated when you get checked going through the X-Ray.
All Co2/HPA tanks will fit any marker. Co2 cartridges will not.
All Co2 tanks will fit any gun meant to be powered by Co2.
A fill station is a bulk CO2 tank, a fill hose and a scale. They are used by trained air smiths and paintball field employees to refill empty Co2 tanks. First the tanks are purged of all remaining Co2, then carefully refilled and weighed. If you are not trained on how to do this, do not attempt, at the risk of breaking the tanks burst disk or damage to you by the extremely cold gas.
No, they cannot.
The cybrid uses Co2 tanks.
"H" is not a size for CO2 tanks
No co2 tanks are sold full.
They need the small sealed CO2 cartridges, not the screw on tanks. but yes they need Co2 to function.
There are a lot of good sites for co2 tanks. One that I prefer is DicksSportingGoods.com they have a lot to choose from in many different sizes. They also have many other things besides co2 tanks.
Yes they do
There is not a place where you can trade in Co2 tanks. Except possibly a pawn shop.