You could use photographic light stands or speaker stands. Be sure to securely fasten the airport to the stand so that it doesn't fall off and get damaged. Plus you'll have to secure the cables running up to the pole. A simplier solution might be purchase a few airport expresses to place strategically around the trade show floor to increase coverage (extend the network).
Thanks for the advice. I like the suggestion to extend the network using two AirPorts. I am confused about how to set it up. I am setting up a wireless network in a conference room that is about 5200 square feet. Initially, I was going to setup just one Airport Extreme, but I think I will do two now. I plan to connect both APs to a single switch. It looks like extending the network range involves hooking one Airport into another - like daisy chaining them, I guess. Since I am going from one switch out to the two, should I just set them up independently and use the same network name (not choose extend the network on either setup)? I want to create a single wireless network so that clients can move from device to device with no interruption. Since both devices will probably be close enough that the wireless spectrum overlaps, should I manually set the radio channels on both or just left them both at automatic? Thanks for any advice on how to set this up properly.