Abdul Rachman Saleh Airport in Malang, East Java province, was temporarily closed at 10 am local time on Friday due to the eruption of Mount Semeru, the Transportation Ministry announced.
"The spread of volcanic ash may stop aircraft engines and endanger flights," said Director General of Civil Aviation Kristi Endah Murni.
The authorities appealed to airlines to compensate passengers whose flights had to be rescheduled or rerouted to the nearest airport.
The mountain as high as 3,676 meters above sea level erupted at 01:38am local time on Monday, throwing ash as high as 2,000 meters for 146 seconds and the incandescent lava slid up to 800 meters to the southeast.
Semeru's eruption in 2021 killed at least 50 people and displaced thousands more.