Great question — answering as the UphillTech team:
Of all the search engines known to me , it can be done with Kiwi . Say I want to fly to Madrid from anywhere in Central + Eastern Europe, I can choose Madrid as my destination and a circle encompassing approximately my suitable departure airports as shown below. Only look to the list on the left as I could not make out any sense in the prices shown on the map. Kiwi has plenty of options, you can move and expand the departure circle freely choose a specific date, date range or anytime make your destination a set of nearby destinations via another circle I suggest you to search for direct flights only, as they have a weird option of connecting two separate tickets on low-cost carriers with a...
Full answer by mts: https://travel.stackexchange.com/a/73710 (CC BY-SA 3.0).
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