they are ( maybe "were") available from Horizon Hobby
The cradle is one of three accessories offered for the XtraEasy training plane.
It may have been discontinued. The accessories were offered at the time the
XtraEasy first came out. They were sold directly from HORIZON HOBBY
and the price was always $ 18.00 US
try horizonhobby.com and if that does not show use the phone
1-800-338-4639-------they do sell things direct