@pallan
I'm sorry to hear you have been unsuccessful. There's always next year and then the year after that. People are usually rejected at the initial stage for 1 of 2 reasons. Either you didn't meet the minimum education criteria or your answers to the essay questions were poor. Did you proof read it several times? Did you have somebody else proof read it for you? Any errors, double words or misspelling will ultimately place a candidates application in the reject pile. Also maybe the answers you provided to the initial multiple choice questions didnt demonstrate the behaviours of a typical BA pilot.
Hope this helps. Best of luck next time.