CREATE TABLE table_39805 ("Airline" TEXT, "ICAO" TEXT, "IATA" TEXT, "Callsign" TEXT, "Commenced operations" FLOAT, "Fleet size" FLOAT, "Headquarters" TEXT)

What is the of Fleet size with a IATA of pr, and a Commenced operations smaller than 1941?
SELECT SUM("Fleet size") FROM table_39805 WHERE "IATA" = 'pr' AND "Commenced operations" < '1941'
SELECT SUM("Fleet size") FROM "table_39805" WHERE "Commenced operations" < '1941' AND "IATA" = 'pr'