My developing site - [login to view URL] - is a multivendor marketplace insists to sell bookable services, or product such as dentist appointment, car rental, etc.
I use FacetWP for custom search which used to be integrated with Woocommerce Bookings. FacetWP works well to find available products by date. FacetWP uses flatpicker for date:time selection.
The user can select date range to find free slots for bookable services, which is fine and works well.
The goodies would be if the end user can search available date range, and narrow the search result by time range. (Flatpicker dos not support such a thing, but with additional custom time text input field would be possible - I assume -).
To be more clear let me have an end user scenario:
I plan to go to hairdresser on next week aka from 03-09-2018 to 07-09-2018.
But because of my regular working hours I will be free only at afternoon aka from 17:00 - 20:00
So I need to find quickly someone who has free time for next week, but only from 5pm.
I'm not interested to see search results of any offer from vendor who has free time according to the date range, but only those who specifically can offer free slots beetwen date range AND time range (from 17:00)
Please have a look at my left widget area at [login to view URL]
FacetWP offers wide variety of building custom filter. What you should find is to get the way to further narrow the search result by the hour range among the filtered date range results.