It is possible the ultrasonic devices mentioned above might be adaptable to aircraft use. The ones I have seen on sailboats have 3 vertical probes oriented in an equilateral triangle that measure wind speed as well as direction. I suppose a static input could be mixed in with it to get an equivalent "indicated" or true airspeed readout...
I don't know if such a system is adaptable to high airspeeds or if it would be more or less susceptible to icing, though...