Airport, prob. won't - Lead issues. Look for Racing Gas,
They are getting really leery of selling Avgas that isn't pumped into a plane lately, both from Lead issues, and they start thinking "What's this guy plan to do with it?"
If anything, check for sources of Racing Gasoline in your town.
Certain stations around bigger towns (I know of three around the San Fernando Valley, Greater Los Angeles there's probably a dozen total) have a pump around back with 105 or 108-Octane unleaded Racing Gas - Trick or Sunoco.
No Ethanol, and a healthy price premium of like $6 a gallon - but if your Dirt Bike or old Muscle Car needs it, they've got it.
In small towns you'll probably have to call one of the local gasoline and oil distributors and get it delivered by the 55-gallon drum full.
Or order it through your local gasoline station. Some of the Delivery Tank Trucks can pick it up at the Tank Farm and have a little space on the back of the trailer for three drums and a liftgate to drop it - or they send a flatbed to bring it out on the same order with the drums and cases of Motor Oil and ATF.