Ive upped long range planes and flown around the entire map. I like the sound of certain engines at 20,000'. P-47Ns and Lancasters come to mind. Ive upped Lancs with full fuel and flown obscenely long missions in them. And the 47N? I love the sound of that turbo-charged R-2800 at 20,000'+. Maybe it sounds weird but its peaceful up in that cartoon air.