To simplify the question, let's assume you don't have to take off or avoid other traffic; you start in the air over San Francisco, and you're the only thing in the sky so you can take the most direct route.
In that case, you'd be flying about ten degrees south of due east.
The movie Bed Knobs and Broomsticks has a flying and time traveling bed (that includes a flying mattress).
6 hours flying
About 9 hours if your flying with Malev airlines and have no-connections.
Usually when you fly from New York to San Francisco the flight takes longer in elapsed time than the trip from San Francisco to New York. Flying from east to west in the Northern Hemisphere usually means flying into the wind, while flying west to east gives a tail wind. Also, the trip flying west may seem shorter because of the three-hour difference between the two locations: 4:44 New York (Eastern) = 1:44 San Francisco (Pacific)
It's not necessary, but that's the shortest way, and that's what all the airlines do.
southeast Southeast
southeast
You'd be traveling South East, SE, since Miami, Florida is east and south of San Francisco.
southeast
west
Roughly southeast
Cardinal direction is North (intermediate direction is north by northwest)
about 10-12 hours depending on which direction you are flying in.
north
Southeast
4 to 4.5 hours depending on which direction you are flying.
You are flying west (start at north, and work your way around clockwise, 90 degrees for every quarter of a circle)