I think you will find that if IAG buy Norwegian BA will expand further at Gatwick. IAG are fairly consistent that London is BA be it LHR, LGW, LCY. I can see Norwegian/Level being responsible for low cost long haul elsewhere in Europe apart from Dublin and Madrid. Norwegian short haul will probably stay as it is apart from Sun routes to Europe from Gatwick. Other minor subsidiaries will be shut. IAG will then have companies serving all markets in a fairly simple and cost effective structure.