Interesting question
The advance of both RYR and EZY will continue, their size relative the the European legacy carriers will increase.
Both the LCC have a massive aircraft order backlog and better costs than their legacy rivals and better costs than air berlin and Norwegian.
Where EZY and Ryanair go toe to toe , the larger carrier will win partly due lack of slots. So five years from now, my prediction is that EZY will have largely disappeared from STN, but will be bigger at LGW, to the cost of BA
RYR will be huge at STN and still be insignificant at LGW.
For other European markets, I expect Scandinavia to go to RYR, Ezy have already backed down at LGW to competition from Norwegian - but ultimately Norwegian will lose out to RYR. SAS will struggle in the fight and shrink dramatically.
Begium will be dominated by RYR, France by EZY - Air France will lose out. SN Brussels will shrink dramatically.
EZY will win in Amsterdam but at the cost to KLM.
Switzerland will stay EZY, Italy will be a bloodbath that Alitalia will still lose. RYR and EZY will share the spoils with Vueling but with RYR the larger of the three in the Italian market in the end.
Spain and Portugal more difficult to call, but I don't see a future for TAP
Five years from now RYR will be bigger than EZY in Germany but both will grow immensely at cost to Lufthansa, German wings and air berlin, the latter may even all but disappear.
The difficult call is UK regions, why? Keeping aircraft with almost 200 seats busy 365 days a year is not the bread and butter of most UK Regional airports.
So EZY with their smaller A319 fleet are better placed and likely to end up stronger away from London while increasing A320 use at gatwick. Although I do expect easy to withdraw from domestic trunk routes from STN. FlyBe, not RYR or EZY, may yet have the real answer for most of the regional airports in UK.
Expect to see more of Flybe feeding hubs that help to prop up air france, KLM, SAS. It will be interesting to see how any ownership change of Aer Lingus impacts RYR.
So in the end both RYR & EZY will be much bigger and are likely to each polarise particular markets, but will not be toe to toe with a large number of flights each at any one significant hub. So Mancheser for example will remain diverse with multiple short haul operators.
FF