The United States' 48 states could easily fit in the desert.  It spans more than 3,000 miles across Africa from the Red Sea to the Atlantic Ocean.

You would have to travel in a plane for over 6 hours to get to the other side... Supersonic fighter jets could make the trip in about 2-3 hours...

Of course,  The Flash could make the trip (and back again) in less time than it took you to read this sentence...how's that for fast!!!