Budget airline easyJet said a surge in business at the end of the summer and a benign operating environment meant it was upping its full year profit forecasts.The firm now expects pre-tax profits for the year to the end of September 2012 to be between £310m and £320m.This compares with the previous range of £280m to £300m.Following the end of the Olympic games, demand from London increased towards the upper end of expectations with the late market and beach routes performing particularly well, the airline said.However, easyJet said it estimated that at current fuel and exchange rates the airline's unit fuel bill for the 2013 financial year was likely to increase by £30-40m. In addition, it said exchange rate movements were likely to have a further £40-60m negative impact in the next financial year.Analysts at Nomura said that as a result of headwinds from current fuel and currency rates, they had altered their forecast for pre-tax profits in the 2013 fiscal year."[It] is of a lower magnitude (£310m to £325m), which moves us close to current consensus," they said in a note."Existing forward bookings are in line with expectations and not a cause for concern, we believe."Ongoing savings from Easyjet lean, the rollout of assigned seating and continued focus on the business customer all offer tailwinds. "On 11x estimated 2013 fiscal year earnings per share, we value the shares at 650p (up from 580 previously)."