X-Plane does it. So can you. There should also be a way to go from the flight directly to the world map, skipping the intermediate nonsense. And it should be instantaneous. X-Plane can. Fewer levels of menus.
Further, if I start a new flight at the same airport, it should start faster if I was still flying around the airport. Why do a full reload? You have the data you need.
Absolutely! Switching aircraft, weather, world map…shouldn’t have to go back multiple levels of menu with long load times.
Because that data gets unloaded. If it didn’t, it might make your second flight from the same airport a lot quicker, but if you wanted to fly somewhere else, it might make you next flight take a little longer to load.
I’m not certain how relevant this is, but last night I did something by accident for the first time: I put my computer to sleep by accident while fumbling for the print screen combo! 
Instead of Windows+PrtScrn I clipped Fn+F12 which is sleep on my keyboard. I was in the middle of an hour long flight, and thought it was lost, but when the computer woke up I was at the menu screen, the flight was still there, not so much as a hiccup.
Keep the last airport, and geography in memory, and it could be as quick, I guess.
I think it should work effectively like slew. Slew doesn’t have any real delay moving you around the world quickly (aside from bringing up high res imagery), so why should new flight selection have a problem slewing you back to where you immediately just were in the previous flight?