Three passengers aboard an Air Malta scheduled for Rome on Thursday afternoon lost consciousness due to "unprecedented soaring temperatures", the national airline.
In a statement, Air Malta said the incident happened while the plane was still on the ground, as a result of "a combination of the extreme temperatures exacerbated by an air-conditioning fault".
The three passengers were attended to by the cabin crew on duty and supporting medical emergency services.
Air Malta said all customers disembarked onto buses and headed back to the Malta International Airport terminal where they were provided with refreshments.
Consequently, Air Malta flight KM614 Malta to Rome and KM615 Rome to Malta are encountering a delay.
Air Malta did not say when the flights were due to depart.