All the swearing, drinking and smart-ass airmen here make me believe that the filmmakers have watched too many Vietnam war films. They certainly don't impress by their research into WW2 USAAF bomber operations! For one thing, a crew drinking as hard as this Irish one and flying with hangovers, would not have survived long in combat. However, all things considered it is not too bad a film even if it falls down on details;
The Bf 109s attacking in the initial CGI scenes carry Eastern Front markings, the constantly used 'Roger that' is not a WW2-era phrase, engine overheating is not caused by the oil pressure rising but on the contrary by the oil pressure dropping causing the oil temperature to rise, US aircrew did of course not have to hold their throat mikes every time they spoke, the proudest possession of any aircrew member is his 'wings' but here some do not wear any on their uniform and others (for instance the aircraft Captain) wear strange wings in the wrong place, the CGI bomber at about 38:00 is actually retracting its tail wheel while landing which would have resulted in serious damage to the aircraft (is it a re-cycyled take-off scene?) - the list is almost endless.
I have somewhat generously given it three stars for entertainment value, but not much else.