CREATE TABLE table_70044 ("Name" TEXT, "Pennant" TEXT, "Builder" TEXT, "Laid Down" TEXT, "Launched" TEXT, "Commissioned" TEXT)

What date was the U21 pennant laid down?
SELECT "Laid Down" FROM table_70044 WHERE "Pennant" = 'u21'
SELECT "Laid Down" FROM "table_70044" WHERE "Pennant" = 'u21'