The attached sketch shows a very simple and easy antenna I made for marine signals on AIS band (162 MHz). It works very good. Each of it's arm is 46 cm long, which is 1/4 wavelength at 162 Mhz.
For Airband, using mid band frequency of 129 Mhz, the length of each 1/4 wavelength arm should be 58 cm instead of 46 cm