They have no money for their tiny fleet let alone planes at US$180 million a copy or what ever it is.
The planes are on order and will be added as soon as they're available. The whole point of the Florida trip is for test flights.
Captain Jerry Kyd, commander of HMS Queen Elizabeth, commented on the initial deployment and the gradual increase in air wing numbers:
We are constrained by the F-35 buy rate even though that was accelerated in SDSR in 2015, so initial operating capability numbers in 2020 are going to be very modest indeed."
So, it ain't the money, it's the availability of the product.
To busy feeding muzzie terrorists at home.