Alright, so i played through the game and i have a few recommendations
1- add a minimap to help with orientation as its very easy to completely lose where you are or add the ability to go higher in the air
2- add a view ability with the mouse to look around and see if you can help find where you are or where you need to be
3- add markers on the ground for finding destinations so they aren't as obvious but so you can have any clue if you're dropping it in the right spot if you arent experienced
4- add difficulty levels so people can play according to how good they are at geography and how much they want to learn
5- add an aiming system as its very hard to tell if your package will hit where you want it too, even if you're right where you think you should be
6- add a country-only mode where you're looking for countries rather than cities
7- add a flag mode to help teach people the flags of each country, whether that be having to find a country based on its flag, or find a flag based on its country
8- remove the markers for places you've previously dropped to, they get very confusing in my opinion
These are all just recommendations on ways i think you can make your already good game even better and more accessible to a wider audience