The Memphis airport is inside the city limits of Memphis. However, it's in the south part of the city, so you can leave the airport and travel 20 or 30 miles in various directions and still be inside...
it is 5 hours from Baton Rouge to Memphis going approximately 70 mph
time markers:
Baton Rouge to Hammond, LA: 30 min (I-12 East)
Hammond, LA to Jackson, MS: 2 hrs (I-55 North)
Jackson, MS to...