The problem of communicating binary information from ground to aircraft viaL-band aeronautical satellite channels is addressed, with particular attention given to the effect of and means of combating diffuse-scattered multipath interference. Differential phase-shift keying (DPSK) is considered throughout. Test results of a recent flight-test program are summarized and compared to theory for uncoded DPSK. We then discuss and evaluate the use of diffuse convolutional codes in conjunction with threshold decoding to improve error probability on the fading channel. Simulation has shown that a power saving of 8 dB may be gained at 10-5error rate for typical channel conditions with very little complexity.