I need advice on a level please

[Tudorp15]

1st off. I am not a huge gamer, but love to play. I been waiting for Birds Of Prey for a year. Glad it's finally here.

Now, again, I am not a gamer, and not very good most the time, but I love to play anyway. I am having a problem getting through a level and it's bugging me, and I am not even sure I am doing the right thing in it.

Level: Hornet's Nest

Question: I been trying and trying to get all the transporter plans shot down. I get to about 28 of them (highest) and then run out of time I assume. It just doesn't seem to be able to get past this. Is there some other thing I am missing? Am I supposed to be shooting these things down to complete the level? Am I supposed to go blow up the ground targets? Anybody got any tips to help get through this level?

Thanks in advance for any help..

T