Using Knack and Zapier to send emails based on USER criteria

Hi Zapier Peeps!!

I am using Knack as a database for various flights. Each flight consists of a departure city and destination city.

I need for a user to be able to

a) submit a form with their name, email address and which flight route they desire (departure and destination city). I’ll do this through Knack.

and then the complicated part...

b) receive notifications based on the criteria they chose in the first step. IE - They’d be notified if a flight from only Vegas going to only Miami is inputted into our Knack database in the future.

Any help would be soooo appreciated.