You did check the elevator controls, right ?
I put together another Coroplast F-22 for my buddy - the one who has the laser cutter that cuts out my airframes for me. MIne is red on top, his is red on the bottom.
Here's what happens when you focus on having the aileron function set up properly during pre-flight - and forget to check the elevator function .......
Coroplast is VERY forgiving.
We'll get some formation flying in once he's comfortable with the plane.