Here's an excellent performing, low cost antenna you can build, paint, and hide in a tree or planter, or anywhere else a piece of PVC pipe might go unoticed.
The Center-Fed half wave offers a shorter overall length (about 50 inches total) than the end-fed half wave designs, and it's incredibly easy and cheap to build.
I used 3/4 PVC pipe from Lowe's and some RG/58U coax from my junk box. You can cut it so the elements are 20-1/4 inches for airband, and do 10 turns for the coil. Just be sure the entry and exit holes for the coil are either on the same side of the PVC or 180 opposite each other. Not 90 degrees out. I used some epoxy to seal the holes for the coil. Instead of fishing line, I sprayed the inside of mine with some of that expanding foam that comes in a can, to hold the center conductor in place. You can use a PVC T or barrel connector depending on where you want the coax to exit the pipe. You can cut an old pop-up sprinkler body, an old caulking canister, or anything similar to protect the coil from the elements.
Another option for more stealthines, go without the upper portion of PVC, use a short piece of PVC just for the coil, protect if from the elements, and just hang it up!
I am getting outstanding performance from airborne signals, and solid (ground) ATC signals from 25 miles away, and intelligible ATC signals 40 miles away.
Here is the website for the Half Wave Flowerpot, with excellent instructions. http://vk2zoi.com/articles/half-wave-flower-pot/