EI @ LGW & Easyjet
Jet2 and Easyjet both flew from Belfast to a range of destination, and generally didnt go head to head. Easyjet didnt go after the Jet2 markets. That was of course until Jet2 decided to launch service onto some of Easyjets markets, Eg Pisa, Palma and a few other's I cant remember specifically. The resultant was that Easyjet lauched head on with Jet2 on Belfast Prague, Barcelona, Ibiza etc.
Easyjet wont react to a competitor unless they are provoked, and dont usually follow carriers onto routes unless that same carrier has offered a specific challenge.. eg Aer Lingus.
Aer Lingus certainly have made cut backs at Belfast and it looks like down to 2 aircraft at the base in winter, but whether the market is soft or whatever, Easyjet know full well that after a sustained period of competition and consistency Aer Lingus will axe the loss making markets. Easyjet wont have to spend nearly as much to market any LGW routes as the travelling public know that Easyjet are 'big at Gatwick'. Aer Lingus while they are good and want to grow have a massively up hill battle against Easyjet.