receiver 52 is carried by the second weather station 20 preferably positioned at ground level 22 proximate the ground target 14 for providing a reference position useful in programming a flight plan for the aircraft 12 the weather data transmitted to the central station 24 for further may generally include temperature relative humidity altitude wind speed and direction data collection time and data collection date the aircraft 12 preferably includes a guidance system 54 as illustrated with reference to fig3 which may communicate with the weather stations 16 20 and the central communications station 24 as illustrated by way of example the guidance system 54 may operate with an onboard navigation system 56 for positioning the aircraft 12 proximate the ground target 14 and for following a prescribed flight pattern 57 as illustrated by way of example with reference to fig4 a over the ground target 14 during the distribution of chemicals as earlier described with reference to fig2 a the aircraft 12 receives data directly from the spread spectrum data transmitter 50 of the first weather station 16 by the receiver 60 of the guidance system 54 as illustrated with reference to fig4 b and by way of example weather conditions can dramatically affect the distribution of chemicals dropped from the aircraft 12 the guidance system 54 operates to provide the prescribed flight pattern 58 and an appropriate modified pattern 62.