The higher the octane rating of the fuel the less "volitale" the fuel is. Basically, it's just as "explosive" BUT it burns slower. That's why high-compression engines run higher octane fuel. I don't know much about jet fuel...but, I believe that aviation quality fuel is leaded, that means a big no-no for fuel injected vehicles or vehicles with catalytic converters. Your best bet is to go to a local drag strip(if available) and get high octane race fuel...if you don't have an internally modified engine it won't do you any good. OR, you may be able to buy some aviation fuel from a small nearby airport...one that deals primarily in crop dusters and things of the like, see if they'll sell you fuel...they may not but you never know.
As far as methane...I'm not sure if you mean methanol or nitromethane...but both of these will destroy carb and fuel injector seals if you don't use special seals/gaskets. Again, with an internally stock engine, there is no need for anything that you can't get at the pumps(good ol' Sunoco 94). I ran a very small nitromethane/methanol mix in with Sunoco 94(I wanna say, 5%methanol/12-15%nitro) in my ATC 200X....that thing kicked ass for awhile...until I destroyed my carb...if I rode it for more than 5 minutes I would have to wait 20 minutes for it to cool before I could start it again...If I rode it for more than 10 minutes, you could hear the fuel in the fuel bowl boiling(never good). Nitro and methanol create a lot of heat.
Stick to the pumps and you'll be just fine.
New Toy- Stone stock '88 T-bird Sport in need of some TLC
1988 Cougar XR-7- HO/T-5 conversion, cracked block prevented from reaching full potential.
RIP '88 T-Bird....firstname.lastname@example.org...best sleeper in So. Jersey, now it's taking a permanent dirt nap.