That is, elements inserted in the timeline between two adjacent reservations/visits that explain how to transit to the next element.

Think of stuff like:

• "go to gate X42 (15 min)"
• "you should take bus XYZ leaving in 5 min to the airport in order to be in time for your flight"
• "leave in 30min to drive to the airport"

This would need an appropriate data model, local transport data (see e.g. public transport, OSM navigation, etc), ideally live transport data to take delays into account, and continuous monitoring of the users position and itinerary.

Probably the most ambitious item on the board :)