Which aircraft was designed as a bomber?

The XB-70 was specifically designed as a strategic bomber for high-speed missions. Developed in the 1950s, its design focused on advanced aerodynamics, with the capability to fly at high altitudes and speeds to penetrate enemy airspace and deliver nuclear payloads. The aircraft’s distinctive delta-wing shape facilitated both speed and fuel efficiency, which were crucial for long-range missions.

In contrast, while the XB-15 was also a prototype bomber from an earlier era, it did not reach production or operational status like the B-1B and was ultimately not built as part of a modern combat strategy. The X-29A was an experimental aircraft focused on testing innovative technologies like forward-swept wings, but it wasn’t built for combat roles. The B-1B, although a capable bomber, is a product of later development and a different generation than the XB-70.

The XB-70's design mission distinctly classifies it among bombers rather than experimental or tactical roles associated with the other aircraft mentioned.