If you do want a frank suggestion, join Slimming World. It's the only diet I have done that took the weight off and because of the type of diet it is (ie relies on home cooking and makes you aware of what you're eating) the weight has stayed off for over 2 years. You should be able to shift a chunk of weight before you go.
Then you can throw yourself from a plane with gay abandon!
Sent through the ether by diddling with radio waves