my thoughts are that yes you've done all the work but your "wingman" has finished off the job, and the team has benefited.

i believe that often the aces would fly higher than the battle and swoop in when they saw a kill for the taking before returning again to the heights to pick another target.

it is unfortunately one of those things that you cant get away from if you play for points. may i suggest that you get into a few league games, where team victory counts, or even better into a squadron where team victory is paramount.......

best idea is to accept that there players like that (i'm sure i've done it on occasion!) but to get on and enjoy the game, and try to take a more team orientated view. if it's dueling you want then that's what the one on one scenarios are for.