As it's confirmed from the airline, Iberia, spanish national air carrier, will not resume flights from Madrid to Zagreb, Zadar and Split in this summer season.
Iberia flew to Zadar from Madrid in the summer season 2019. two times per week until end of August, the route was introduced last year but this summer season, due to the pandemic situation, the airline will not operate regular flights on this route.
The only year-round route to Croatia was to Zagreb, and the airline is not planning to resume flights on Madrid - Zagreb route as well. Right now, Iberia is selling one weekly flight (every Friday) in the winter timetable, but those flights will, most likely, be canceled as well, which means that there will be no direct flights between Spanish and Croatian capitals.
It was possible to fly everyday between Madrid and Split in the summer season 2019., but due to the lower demand airline will not resume flights on this route as well.
The only route to Croatia which is now operating is between Madrid and Dubrovnik, the route will continue to operate through August as well. There was 3 weekly flights, but now airline will add two more, total of 5 per week (every Monday, Wednesday, Friday, Saturday and Sunday). Just for comparison, there was 15 weekly flights in the peak of the summer season during the 2019.!