I've found the following secret items in Carrier Airwing.
I was wondering if there are any more, because in the graphics viewer in MAME there are small objects (meat, Mobichan, a milk jar?) that look like bonus items, but I haven't seen them.
And if not....well then this is now a guide for the secret items in the game . 10,00 points each!
In my last run I missed the item in the 2nd screenshot (man) and the 3rd screenshot (star), plus the rabbit which is also on stage 3. You're missing a few more than just the rabbit.
Checking my replay:
Stage 2 - At the very end of the highway where you fight the mid-sized helicopters at the top of screen the astronaut (mobichan) is revealed.
Stage 3 - Destroy all the trees in the first half of the stage and the rabbit is revealed.
Stage 8 - Once you reach the oasis (palm trees) there should be some houses in the foreground. The between last house and the water is an astronaut with flags.
Stage 9 - In the last part of the stage with the green control rooms (hanging from the top and standing on the bottom of the screen) there should be a Yashichi on one of the bottom platforms (in a turret).
Stage 10 - On top of the first form of the final boss, the red turret should reveal the last bonus, Yashichi #2.
. 10,00 points each!