In an emergency you are not required to have a license to use HAM frequencies...I am fairly confident this would apply to the aircraft frequencies also, but I cannot say for certain how the rules apply for frequencies outside of the HAM bands.

5 watts with the supplied antenna is not going to give anywhere near 50 miles of general coverage. A much better antenna AND a very good location would be required for that sort of coverage. 5 watts on the side of a mountain to an aircraft overhead is reasonable though.