The U.S. Air Force is evaluating prop-driven aircraft, with the intention of forming a squadron of suitable aircraft for "light attack" duties. One of the aircraft being presented for consideration is an updated (electronics and weapons systems) OV-10, whose design is now owned by Boeing. The OV-10 was originally developed, early in the Vietnam war, to provide what the air force is looking for now. Unlike other aircraft used, the OV-10 was designed specifically for irregular warfare. That's a big reason why it is still used, and is being considered for reintroduction by the U.S. Air Force.
The OV-10 is a 6.5 ton, twin prop aircraft that could carry over two tons of weapons and stay in the air for three hours per sortie. Wingspan is 40 feet (12.2 meters), and length is 41.6 feet (12.7 meters). The first one was delivered to the U.S. Air Force, for use in Vietnam, in 1968. The last one was produced (for export to Indonesia) in 1976. The U.S. Air Force and Marines were the primary users of OV-10s, and the last of these was retired, by the marines, in 1994. Over a hundred were exported to Germany, Thailand, Colombia, Venezuela and Indonesia. Several dozen of these are still in use out of over 300 manufactured. In Vietnam, the OV-10 was used more for reconnaissance and directing air and artillery strikes, than in using its own firepower. But that's what irregular warfare was all about, finding an elusive enemy, and killing him. That's what the OV-10 was designed to do, and did it well.
Resurrecting the OV-10 is a side effect of the success the air force has had with large UAVs, especially the Predator. Prop driven aircraft are much cheaper to operate than jets. A Predator costs less than a tenth, per hour in the air, that an F-16 does. The OV-10 would provide similar economies, especially since it could also carry 500 pound JDAMs and hundred pound Hellfire missiles. Smart bombs make an aircraft like the OV-10 a lot more useful, and economical. The OV-10 could also carry a targeting pod, like the Sniper XR, which weighs about 450 pounds. This gives the air craft superb reconnaissance capability, backed by smart bombs and guided missiles to immediately attack targets found.
The air force is seriously investigating aircraft like the this because money has become a big issue these days. If you currently have jet fighters and bombers spending over 10,000 hours a year over Afghanistan and Iraq, at a cost of over $40,000 an hour, when you could have OV-10s do it for a few thousand dollars an hour, what would you do? We're talking some serious money here, and the air force, and even the navy (which used dozens of OV-10s off carriers during the Vietnam war) is definitely interested.