How do you get past level 3?

hello rick welcome to the forum. as for your question you just do as the directions say. ive never really done the missions

Do you mean rank our the game?

For rank eep killing and bombing. There is two numbers in white at the top of your screen. E.g. 1234/5000 that means you have 1234 points but you need to reach 5000 to get your next promotion.

For the game keep trying sometimes it's about hard they start right on you, but sometime they start far enough away that you can get them.

hes talking about the single player missions not the ranks i think

Rick, for the third practice round, you have to kill the enemy plane, both tanks and bomb he hangars.