Bonus mission 4 problem
 

I destroyed all German forces on the airfield and all the planes too, yet the objective "destroy all German planes" remains marked as unfinished. I started the mission by sending all three tanks directly onto the airstrip, sounding the siren and then destroying the two bombers that tried to take off; is that not supposed to happen? What should I do?

I used a trainer to get through, it was a bug.

I noticed the same thing on mine, said I had to destroy all the planes even though I did. But after I took out the last 88, your bombers come in, and bomb the place. After that happened, the objective was checked off.

Dont know if youve done that or not, but worked fine for me.