My Thoughts about skill:
1) As a model of WW2 air combat the idea is to shoot down the enemy in the largest possible numbers; Borrowing admittedly from ww1 Richtofen, his ideal kill would be a reconnaissance plane that did not even see him going down in flames. That takes skill.
2) The Dogfight but inevitably 2 different aircraft with different e states.
3) The Fur ball: Hugely subjective involving allot of SA among other skills. This lends itself to all the running and picking type criticism.
4) Koth. Same aircraft and same initial e state at the start. Closest thing we have to a skill comparison IMO. TOC champions I have known have all been MA beasts.
Skill from a fighter perspective can be measured in many ways but one must be able to perform ACM and defense ACM in all areas.
1. Shooting down as many as possible is great, but in real life you only die once, therefore in video games staying alive while getting a lot of kills is a measure of skill you can define. Its not the "be all end all" in the MA, because plane choice can make it much easier or harder for you. Players who fly slower planes and have a good K/D are much better IMO than players in speed demon cannon monsters.
2. Special events skill - in special events they are designed to mimic real battles. Its squad oriented and planes are more evenly matched, teams are working together much better. therefore getting a lot of kills in special events and surviving is a good measure of skill. KOTH is not always evenly matched, a player comes in higher and attacks you right after you just got a kill. Its about killing quickly so you can get the advantage over others while they are still fighting. It does take a lot of skill in many ways but isnt the be all end all. Combat Challenge was a great way to measure pure furball combat skill with balanced planes AvA. Now those are a lot of fun!
MA skill is all about knowing the situation and how to attack it. Using plane choice for certain sorties over others. Being good in many planes. Having great SA knowing a speedster can come around at any time. Being able to reverse effectively so you don't have to always fly BnZ planes and can escape or get counter kills. Being able to outurn planes in BnZ fighters. Being able to fly higher ENY planes and surving while getting kills and improving accuracy and K/H. Those are all what can be defined as having a lot of skills in the MA. IMO. A lot of players hide behind EZ mode fast planes with huge cannons for quicker kills. It can be defined for a lot of people what is the best, but the MA is still not the "be all end all" because of plane imbalance, kill messages, dar, and team imbalances that can give players advantages over others.
1v1 skills - these are different than the above though do help. Many players who are great at 1v1 aren't so good in the MA because they get picked a lot trying to 1v1 everyone. Many of them don't want to fly to stay alive in the MA so they get picked often, and in many cases fly harder to run planes. 1v1 skills is representive of a great stick, but they may not be the best in furball or "staying alive" type of special events due to SA and poor plane management.
Being great in all of these categories is what makes for the most skilled fighters, IMO.