Two planes from an Indonesian acrobatic air team clipped wings and crashed during a practice session ahead of an air show in Malaysia.
The pilots from both planes ejected from their aircraft after the jets went out of control and landed safely with their parachutes, said a Malaysian defence official.
A house and a car caught fire due to falling debris from the plane, the organisers of the air show held on northern Langkawi island said.
The four pilots are under observation at a hospital in Langkawi.
Malaysian defence minister Hishammuddin Hussein visited them at the hospital and tweeted: "Thankful that all 4 pilots are safe, their spirits remained high."
The Indonesian team is one of five scheduled to perform at the Langkawi International Maritime and Aerospace Exhibition, set for March 17-21.