For the Micro Skydiver a high lift, 1.2m wingspan airplane is plenty big enough. If it can carry 10 oz. you are good to go. For example you can use the 1.5m FMS Cessna, 1.3m Carbon Cub, 1.2m Timber X 1.2m, 1.4m Piper J3 Cub or Grasshopper, 1.2m Decathlon, 1.4m Freewing Pandora, 1.5m DHC-2 Beaver, 1.5m Kavan Pilatus PC-6 Porter, 1.62m Nexa Piper PA-18 Super Cub Burda and many more.
For the Standard Skydiver a high lift, 2 meters or + wingspan airplane is what you want. If it can carry 1kg / 35oz. you are good to go. For example you can use any 2m or + Piper J3 Cub, the 2.45m Black Horse Super Decathlon, 2m Hangar 9 Ultra Stick 30cc, 2.1m E-Flite Carbon-Z Cub SS, 2.357m Fairchild Model 24 Argus, 2.21m Nexa King Quest Kodiak, 2.24m Black Horse PZL-104 Wilga, Pilatus Porter C-6, 2.71m Piper PA-18 Super Cub and many more.
Of course, the bigger and more power the faster you get to jump altitude.