Cathcart Shoots Back

It's the second decade of an alternate 20th century. The British Empire is at war with the German empire, and the whole thing had turned out to be a bloody mess. Mister Midshipman Basil Dumbarton Cathcart arrives at the Shoreston Hill aerodrome, eager to take up his duties aboard His Majesty's Airship Yukon. Unfortunately, he no sooner pays off his taxi driver than enemy aircraft sweep in, low and fast.
Their machine guns spit death, and their bombs shriek down through the keen morning air. Explosions rip up the runways, obliterate the field's fighter aircraft, level critically important buildings, and leave countless personnel dead. The field is crippled, a sitting duck on a millpond. Cathcart must fight back, but how?