I know of one case where a person crashed a plane and survived and ended up burned badly all over. If it were me considering that method I would wonder if there was a way to jump out of the plane while it is very high, but not over trees that can break the fall- of course then the plane could hit someone else- well it's almost impossible to find a method without holes in it- jumping out of a plane high over the ocean might work- that sounds like it could work- again hopefully the plane wouldn't hit anyone. Trees can really break your fall so I wouldn't try this over land. Personally I would consider abandoning the making it look like an accident part of it- as it is in the u.s. in 2020 there were 1.4 million documented suicide attempts and about 48,000 successful attempts- which is 1 in 29, which is a 3.4% chance of an attempt working on average. So the odds of an attempt working are very low overall, but this is mainly due to so many impulsive attempts that were not well researched. With it being so difficult to pull off I wouldn't make it tougher by trying to make it look like an accident. Of course some methods have a lot more chance of success- some say firearms are in the 75-80% range, and some say hanging is about 70%, but it's so difficult to track that these numbers are educated guesses at best- and may just be flat out guesses- my gut tells me the real numbers are lower, but who knows. If you could fly down to the antartica and jump out of a plane then if the fall doesn't kill you you can be confident of freezing to death- this might be the most foolproof method I have thought of so far, but it's not entirely realistic for most people.