What he said. I can build almost an entire turbine aircraft without buying anything from a hobby manufacturer. A lot of my purchases go to mcmaster, only cause they are marginally more than going to the manufacturer direct, and I only have to pay shipping, no taxes.

G10, stainless steel sheet, most nuts bolts screws, washers, festo fittings, airline t's, air line, fuel line, axles, adhesives, etc etc come from Mcmaster.