The dynamics of aerial combat are changing due to several recent technological developments. The F/A-22 was designed to combine supersonic cruise speed to rapidly reach or retreat from the combat zone with stealth and long range weapons. The goal is to literally blow the opposition out of the sky before he even knows you're there. It'll also have shorter ranged missiles and a gun for combat at different ranges. From what I've read, the plane is very maneuverable. The top speed is said to be less than Mach 2, but top speed isn't an especially relevant parameter.

Another fairly recent development is the smart helmet, like the Joint Helmet Mounted Cueing System. This is especially useful for shorter ranged engagements. It combines the functionality of a heads up display on the helmet with the ability to slew missile seeker heads to match where the pilot is looking*. With this capability, turning radius becomes less important because you can literally shoot over your shoulder at someone behind you. You don't have to worry as much about getting on your enemy's "6" if you can shoot over 100 degrees off boresight. The gun is a last resort weapon for those occassions when you're either too close to fire a missile or you've already shot all of them.

Back in the late 1950s, the military dropped the cannon from new fighters like the F-4 Phantom. Instead, they depended on missiles. However, the results were poor in part because the missile technology of the day was poor. The Air Force started equipping their F-4s with gun pods and later added an internal gun as standard equipment.

Based in large part on the research of Col Boyd**, new fighters developed after the F-4 incorporated high maneuverability with missiles and a gun as standard equipment. This research was very important in the design of the F-15, F-16, F-18, and to a lessor extent the F-14. Based on the Israeli experience in Lebanon (the last big dogfights in history) where they shot down over 80 enemy fighters with no losses, the research seemed to pay off well.

The F-15 was designed as an air superiority fighter capable of besting anything else in the sky. It has performed that job very well but isn't very flexible, so they created the F-15E Strike Eagle to provide long range strike capability while still retaining a good air-to-air capability. The F-14 was designed for long range fleet defense with maneuverability as a lessor requirement. Following the 1991 Gulf War, the Navy added an air-to-ground capability to the plane to increase operational flexibility. The F-16 & F-18 were designed as lighter weight, lower cost fighters that combined air-to-air and air-to-ground capability. To date, both planes have primarily been used as air-to-ground planes. I'm not certain if either plane has shot down a single enemy fighter, but then there hasn't been many opportunities.

UACVs are getting a lot of attention, but all that I've seen to date are for the air-to-ground mission. It might be difficult to give one the all-aspect situational awareness necessary for air-to-air combat.

*Attack helicopter crews have had look to shoot helment capabilities for a long time. The Russians were the first to fit that capability to fighters, starting with planes like the MiG-29. The US military is fielding those helmets now and they're proving very popular with the pilots.

**Col John Boyd was known as "40 Second Boyd". Dating back to the 1950s, he'd challenge any and all other fighter pilots to a dogfight, allowing the opponent to start on Boyd's 6. Within 40 seconds, he'd be on his opponent's six. He was able to defeat all comers except one who managed to hold off Boyd for 40 seconds. He also created the OODA Cycle.