This is NOT a duplicate because this question does not mention the bifrost while the other question does. The two questions have very different levels of abstraction and are thus very different from each other.
In Avengers: Age of Ultron, Thor leaves at the end by flying up into the sky and leaving an imprint burned into the ground. Stark comments that Thor has no regard for lawn maintenance.
I noticed other times when Thor flies without burning a mark in the ground.
Why does Thor burn a mark in the ground during some flights but not during other flights? If the answer is that he only burns when he is going off world, then what specifically is causing the burning? How does the mechanism work?