A war between Ryanair and Vueling could well be in easyJet's interest, as at this time easyJet management are watching with caution what the competing low costs airlines are planning. easyJet have been especially interested in what Vueling have been up to re Rome, and Norwegian in LGW and FR at STN. FR chasing Vueling out of town in respective markets would mean that easyJet have ultimately got FR to compete with rather than Vueling, which is a much closer match to them in terms of service etc
It may come down to who has the most cash and a willingness to sustain losses.
Oil prices have dropped because of Iran issue so that could have a sizeable impact in coming months.