Flight Booking App Connections To Google? + Formula Calculations?

Application is a flight booking/reservation system for a small flight school

I need to configure the following:

  1. In the ‘from’ and ‘to’ fields in the screenshot below I need to configure/call airport names/codes across the United States and Canada. How can I do this?

  2. Using this information I need to calculate the total distance in miles between those two airports and display it in HOURS based on the user-inputted aircraft profile average airspeed in MPH. How can I do this?

  3. Depending on the 1’st drop down menu setting (Round Trip/One-Way/Local Tour) I need to display/hide certain fields and or make other fields editable. How can I do this? Conditions?

  4. Based on the calculated distance between the two airports in miles/total time enroute, I need to run a calculation/formula to display TOTAL cost based on user-inputted Aircraft profile “hourly operating cost” * time enroute PLUS i need to display cost if the booker has 1 passenger, 2 passengers, or 3 passengers seperately flying with them. Formula: (hourly operating cost * total time enroute / # of people on board) How can I do this?

All help much appreciated.

Thanks!