I created this web app originally for designing Pookkalams, which are intricate floral designs made during the Onam festival in Kerala, India. Pookkalams are made using various types of flowers and are laid out in beautiful, symmetrical patterns on the ground.
I think you used standard bus route search with JFK and Heathrow. OpenStreetMap suggests Lisbon since the departure and destination are on different continents, providing a route in close proximity to the destination with access to the sea.
If you prefer the flight path, you can visit dev.sitinshade.com/flight [beta].
Backend: Node.js
Calculations are performed based on the azimuth of the sun and the bus, taking into account the movement of the bus and change in time.
The hard part was obtaining information such as solar azimuth, altitude, declination, hour angle, etc without using external APIs. Spent around 5 days implementing backend.