You may consider building your own 1/4 wave ground plane or even a J-POLE
The basic math for 1/4 wave antenna is quite simple
1/4 wave = 234 divided by frequency or to arrive at a proper antenna length
If not there are lots of antennas on the market cut just for the airband personally I would stay away from the so called all bander if your serious about ATC !
I use the Custom tuned 5/8 wave LARSEN SUPER BASE
http://wingsandwheels.com/page14.htmI looked around for you to find a cheap well constructed Airband antenna and came up with this one (The Airband J-Pole) $33.00 at
http://kb9vbr.com/products.phpPrice is right and it looks like he did a nice job !!
Anyone have this antenna ? let us know

73s
Glenn KB6HLM Las Vegas, NV