Why not park the car far away from the garage door before you start painting.You can also drape plastic or a couple sheets over the car to protect it.If you get the paint off the car within a few minutes,you'll be ok but don't take that chance.You can use laquer thinner to remove accidental overspray or drips of paint,but rub very gently with thinner soaked rag.I've never used it for paint removal,but mayonnaise works really well for removing bugs,tar,and asphalt residue that occurs when driving over a recently patched pothole

1) you don't paint outside in windy conditions.

2) Once paint is on the door it won't blow off again, if it does it's poor paint ot you've used to much.

3) Don't leave the car anywhere near where you are painting

Have you thought about moving the car first ????

If you dont get it off right away. It will ruin it.

I am thinking of painting the garage door another colour.

Also

If I'm waiting for the paint to dry but if its windy, will some of the paint from the garage door can be blown off and onto the floor or car ,causing a mess.

How long will the paint dry before parking back into the driveway?