I spotted this last night when attempting to book a flight to Gatwick in March asa flight for an onward connection.
Tweeted easyJet today, and got this reply "we offer certain routes for specific seasons, Liam and our Aberdeen to Gatwick route flights will be stopping after Winter. However, you may be able to find alternative routes on our route map."
Really disappointing - a real loss to AIA - wonder have hard the management tried to hold on to this route! Obviously not hard enough.