I monitor many radio transmissions thru the “New York”, “Washington”, & “Cleveland” ARTCC centers. I hear many flight identified as “CACTUS ####” or something that sounds similar to that. What airline are they referring to?
US air. they Bought America West and kept the AW callsign
Other way around. 
America West bought US Airways, kept the US Airways name, and the America West callsign and ICAO code.
BL.
Thanks for the information.
Yup- I was wrong.