How to put a flag pole in bed ??

What's going on guys.... Happy Fourth of July! Heading to a truck show this weekend and I figured I am going to have an American flag flying out of my bed for the Fourth of July weekend! I mocked up the flag and flag pole on the left front of the bed (behind driver)using zip ties and using the lower strap down hook and the hole on the bed rails and drilled holes into the wooden flag pole and put 2 heavy duty Zip ties through each hole. But I am wondering if there is a more secure, better way to do this. The drive is about 1 hour away and we are all heading down on the highway so it will probably be seeing 65-70 mph.... I drove it around tonight up to about 60 and everything looked good. Is there a better way to mount the flag though? I really wish I could get it in the center of the bed right behind the rear window. But can't figure out a way to do so without doing modificiations to the bed which I don't want to permently do anything to the bed. Thanks guys

I was just talking to a guy with a ram the other day at the gas station with a flag pole in the back wish I would have paid more attention now.

Hahaha damn! Lol.... I will defiantly suffice with the zip ties that are feed through the holes I drilled out of the wooden flag pole, but I just want maybe a little bit more piece of mind doing 70 down the highway. Maybe some parachute string? Wire? Also, hopefully my flag pole which is about 1.5 inch in diameter will be able to take the beating and not break. Was thinking I could maybe boobie trap something to the pole in case of an event like this happening.

Happy 4th of July guys It sounds like gunshots outside my house right now

Just build a square frame that will sit in your bed, with either wood or pvc. Then make a flag poll holder in the middle with a metal tube or pvc.