LHT... do you mean LHR? London-Heathrow? You're better off looking up airport codes, not guessing.

I would say to keep an open mind. Africa via Europe is indeed a common route, but LH is larger than you may think, with flights from FRA to JNB and seasonally, MUC to CPT.

As for your upcoming trip, WN has a nonstop MEM-TPA as well as MEM-MCO. If loads permit, consider those options. Better yet, take a look here: Memphis International Airport - Wikipedia, the free encyclopedia - pretty much every airport has an "Airlines and Destinations" page to help you figure out where you can get to and on which airlines.