Just in case some of you haven't seen this, the above airlines are moving to the North Terminal, this may affect some of you if you have booked a hotel at the South Terminal, although the internal train only takes a couple of mins.

From the Gatwick airport site.....
If you’ve flown from Gatwick before, you’ll know we have two terminals: North and South. Most airlines operate from just one or the other. As part of our on-going transformation programme to improve the airport experience for our passengers, three airlines will soon be moving: British Airways, Virgin, and some easyJet flights.

The changes will take place over two days, and we're working hard to make sure you experience no disruption.
From 24 January 2017:

All easyJet flights will depart from the North Terminal

*From 25 January 2017:
All British Airways flights will depart from the South Terminal
All Virgin flights will depart from the North Terminal