I think the preceding answer is too simple, as the answer is of course it depends.
If you are flying an aircraft designed to carry less than 10 passengers and you stay in the UK charge VAT at full rate of 20%
If you are flying an aircraft designed to carry more than 10 passengers then zero rate.
See guidance from UK tax authorities
HM Revenue & Customs
The best advice is always to seek paid advice from a VAT specialist, as then you describe your circumstances, and you can sue them if they get it wrong.