The R.38 class (also known as the A class) of rigid airships was designed for Britain's Royal Navy during the final months of the First World War, intended for long-range patrol duties over the North Sea. Four similar airships were originally ordered by the Admiralty, but orders for three of these (R.39, R.40 and R.41) were cancelled after the armistice with Germany and R.38, the lead ship of the class, was sold to the United States Navy in October 1919 before completion.

On 24 August 1921, R.38 (designated ZR-2 by the USN) was destroyed by a structural failure while in flight over the city of Hull. It crashed into the Humber Estuary, killing 44 out of the 49 crew aboard. At the time of its first flight it was the world's largest airship. Its destruction was the first of the great airship disasters, followed by the Italian-built US semi-rigid airship Roma in 1922 (34 dead), the French Dixmude in 1923 (52 dead), the USS Shenandoah in 1925 (14 dead), the British R101 in 1930 (48 dead), the USS Akron in 1933 (73 dead), the USS Macon in 1935 (2 dead), and the German Hindenburg in 1937 (36 dead).