Budget car rental

[rpbert1]

I have a compact booked with Budget at MCO. QWe normally arrive at 4 pm, but this year we are arriving 11pm. Is there a chance they may be out of compacts and we get a better car, as a lot of flights from UK all arrive earlier in the evening.
this is just a thought, as i booked a compact as it basically does the job , but an upgrade for free would be nice