Someone put this on our company forum.
As one of your customers I can only agree its a mess, not just in the States but worldwide.
The history is that Thomson Airways was rebranded as Tui Airways to fit into the German parent group, and some bright spark decided that the callsign needed to change too, but not the TOM because that was too difficult ( expensive).
It has been approved at ICAO, but uptake amongst ATC is poor to say the least and I have every sympathy!
