The AT-18 was a specialized training variant of the Lockheed Hudson produced for the United States Army Air Forces (USAAF) to serve as an advanced gunnery and navigation trainer.

In May 1942, the USAAF awarded Lockheed a contract for 300 of these aircraft, which were developed from the A-28A and A-29 airframes. The production was divided into two distinct configurations based on their specific training purposes:

AT-18: Gunnery Training and Target Towing

The majority of the order (217 aircraft) were designated as AT-18s and used primarily for gunnery training.

• Armament: These aircraft were fitted with a Martin electrically-operated dorsal turret housing two .50-inch Browning machine-guns. This turret was becoming the standard on many USAAF bombers, making it an ideal platform for training gunners.
• Secondary Role: These aircraft were also used for target towing.

AT-18A: Navigation Training

The remaining 83 aircraft were designated as AT-18As.

• Primary Role: These were used specifically as navigational trainers.
• Design Difference: To accommodate this role, the dorsal turret was removed, and the area was faired over.

While these aircraft were officially trainers, they still retained the robust performance characteristics of the Hudson, with the AT-18 reaching speeds of 272 mph.