I have a lot of experience using 3M #8115 panel bonding adhesive, it will work. But, you really have to have a $70 gun to be able to mix and apply it. You could buy a cartridge and cut it open, then mix it by hand wasting most of it. Thats about $27 and a hassle. You have to remove all the paint from both surfaces in the area of the bond. And you need to find a way to clamp it tightly, (some screws?), while it sets. The vehicle should remain stationary for about 24hrs.
We used to just tack them back on with a mig, they could probably do this while you wait. It would be much quicker and easier.