It''s 1917, and Captain Stanley Woolley joins an R.F.C. squadron whose pilots are starting to fear the worst: their war over the Western Front may go on for years. A pilot''s life is usually short, so while it lasts it is celebrated strenuously. Distractions from the brutality of the air war include British nurses; eccentric Russian pilots; bureaucratic battles over the plum-jam ration; rat-hunting with Very pistols; and the C.O.''s patent, potent cocktail, known as ''Hornet''s Sting''. But as the summer offensives boil up, none of these can offer any lasting comfort.