Table: aichi_b7a_stats
Columns: aircraft_type
national_origin
1st_flight
in_service
retired
built

Question: how many Curtiss XBTC aircraft are retired?
SQL: SELECT COUNT("retired") FROM aichi_b7a_stats WHERE "aircraft_type" = 'Curtiss XBTC'

Question: How many Airspeed Fleet Shadower aircraft are retired?
SQL: SELECT "retired" FROM aichi_b7a_stats WHERE "aircraft_type" = 'Airspeed Fleet Shadower'

Question: What is the origin of aircraft in service in 1943 and retired in 1954?
SQL: SELECT "national_origin" FROM aichi_b7a_stats WHERE "retired" = '1954' AND "in_service" = '1943'