Yep, your hitbox for taking damage only includes the center bit, not the wings; however your hitbox for collection does include your wings. This is intended to skew advantage to the player, but i can see how it can be a tad confusing. Also protip: your plane can fire at an angle; notice how your plane turns when moving. If you get into a situation where there are too many enemies in a certain part of the screen, you don't actually have to move in front of them to clear them. Try holding a direction key and tapping the fire button when your aiming laser is on top of enemies, then holding the opposite direction before you get too close.