I have a black Mickey one that I bought in DL in Ocotber of 1998 and it is still on my car intact. A friend of mine bought one down at a CoD in WDW, but the ears wre ripped off after a few months. The Disney Stores do sell them, surrently in all black, all red, all yellow, or the "flag," as I call it. If you see one, buy a spare (I bought one at the store where I work when we got a shipment in one time). I don't know what the shipping is on something like that, but you cold call WDW or DL merch number to find out.
I have no trouble getting mine on or off. I took the plain on off for the holiday and put on the one with the Santa hat. I am really bad about washing my car, but I think the antenna screws off if i wanted to go to a drive thru car wash.