Here are several websites featuring useful information about rocketry and free flight. If there is some material or product you need for that specialty airplane or rocket, these are the places to find it!
INAV – Indoor News and Views is the ultimate repository of indoor free flight aircraft design, construction, and flying resources.
HPA – Hip Pocket Aeronautics discussion forum for free flight and ultralight R/C topics.
Flite Test – Flite Test store and forum for resources on low-cost R/C design, construction, and flying.
Volare Products – Supplier of excellent free flight kits, flying accessories, and Tan Supersport Rubber.
Indoor Specialties – Ray Harlan’s web store for indoor free flight construction and flying equipment.
Hobby Specialties – The exclusive outlet for OS Film indoor model covering material, the lightest commercially available covering.
NFFS – National Free Flight Society, the governing body of indoor and outdoor free flight competition in the United States.
AMA – Academy of Model Aeronautics sanctions model aircraft activities in the US.
NAR – National Association of Rocketry sanctions model and high power rocketry in the US; their website features design and flying resources for rocket gliders.