I second the vote for the small 4X8 trailer from harbor freight. Build and paint a light weight wood box and configure the inside to hold your planes. You can use PVC pipe to make the racks to hold the planes in the box. You may be very surprised to see how much you could get in a trailer like that. That trailer would not weigh much at all and wind resistence would be minimal as well.
Check this out. Scroll down a little.
http://www.xtremeflyer.com/forums/th...id=661&start=1
Also Look Here
http://www.flyinggiants.com/forums/s...ad.php?t=57105
Build one of these to hold your planes.