I have the luggage rack on my tour pack so I just bend them over and tuck them under the edges of the rack.

 

The Harley cover I have for my ultra has slots for the antennas, then closes around the antenna with velcro.

You can clip the round tip of each antenna into the rear luggage box chrome locks and close the lock and the antenna tip stays at the edge of the lock when closed.

Steve O

 

Harley used to make velcrow straps that fastened around the top of your antennas and then after bending the antenna over you hooked it to the grab handles of your seat. I don't know if you can still get these straps but they would be easy to make.

 

The Harley cover is a nice piece but will take up a whole saddle bag on a trip. I use the Exigent cover. Very nicely made (and in the USA!) Takes up 1/4 the space in your bag.
Heres a link if anyones interested.EXIGENT