1) Ante 1941 2) Antebellum 3) Arms buildup period 4) Before hostilities 5) Before things got out of hand 6) Describing the Edwardian era 7) From the 1930s 8) Like 1930s architecture 9) Like 1930s prices 10) Like some coveted apartments 11) Period before 1914 and 1939 12) Period before hostilities 1) Antebellum 2) Antebum 
Before World War II (with all due respect to those who served in other conflicts).
[adj] - existing or belonging to a time before a war
adjective existing or belonging to a time before a war; `prewar levels of industrial production`
before the war: prewar prices.