The last pre-war aircraft purchase comes in 1941, when 9th Bomber Squadron trades in its Martin B-10s for North American B-25Cs:
Built for medium to high altitude bombing, the Texas B-4 variant was also adapted to carry torpedos to strike naval targets from on-shore bases. Several torpedo types could be carried, from smaller short range weapons in the bomb bay to larger long range weapons slung under the bomb bay (the doors had to remain partially open for this practice, reducing range and speed.)
It was better suited for both missions than the older B-10s.
Examples shown are from C and A Flight, 9th Bomber Squadron. The 'tag number', a combination of the last two digits of the purchase year and the last two digits of the serial number, are visible on the rudder.