Me thinks there may be a bit of creative speak here. I would think the letter means that WAC has access to, or rather Cabair has access to the fleet as you describe not that the WAC fleet is about to change to that.
There is a big choice of aeroplanes out there to use - particularly if the boss man were to run a ruck of GA aircraft leasing businesses and happen to lease them to his other company..... Confused, you will be!