There shouldn't be any VAT on a glider which leaves the country that the VAT is applicable to. ie No VAT on a glider purchased either from a factory or individual if it is exported from that country. However when it arrives at the border of the country that you are importing it to then the local VAT or GST applies to the purchase price

Which you can claim back in that country if is going to be owned by a VAT or GST registered club or Company/Individual.