Levels 10-20 have a sharp learning curve to say the least. Planes do not make any difference unless you are turn fighting. They do provide the ability to carry more ammo and one extra bomb though. In a head on fight any plane will suffice, just keep playing and soon you will be one of those high ranked players.
Stay away from dogfight matches until you have saved up for better planes, and practice head on shooting against better players. You will suck at first, but slowly you will find a way to beat them and become better
Try to line up and fire bursts move change lines and repeat.
Good luck and I hope to see you in the air