You can still buy modest sized balsa and ply kits and short kits for electric powered RC from Manzano Laser Works and Brodak and a fair amount of out of production kits on Ebay and club flea market events. You can download plans and instructions from Outerzone and have them enlarged to any size desired for scratch building. You can order Cleveland plans and build beautiful scale models, in various scales. if you have the building skills to use them as the basis of builds. You can search out sources of balsa and play, covering materials paints and adhesives, fasteners and accessory items. IC Engines new and used are still available although fuel is quite expensive now and sources are fewer. You can search classified sections on RCU and RCG to find a lot of what you might want. It seems that large IC model flyers are now sourcing ARF models more than building.