According to Gatwick's Terminal Information page
, there are four airlines flying to Sharm el Shiekh from Gatwick:
Destination Airline/Tour Operator Terminal Code
Sharm el Shiekh Monarch Airlines South MON
Sharm el Shiekh Thomas Cook Airlines South TCX
Sharm el Shiekh Britannia Airways South BY
Sharm el Shiekh Excel Airways South XLA
Air Atlanta is not listed there, but Excel Airways has a few 757's and 767's on lease from them so the flight might be flown by Air Atlanta on their behalf.
Air Atlanta operates 747's, 757's and 767's (about 35 in total).
Reykjavik Aviation Photography - Just bring the aircraft to us and we'll photograph them! :-)